And yet the DNA on the snap matched BKs check swab somewhere in the 50+ Octillion range. IMO, but also fact.Dr. Larkin wasn't talking specifically about BK because they did not have any DNA evidence to examine at the time. She WAS talking about possibilities that could happen from the processing of DNA and why it was necessary for the defense to be able to examine the evidence. She also spoke about how relationships are determined in IGG which is a combination of science and also experiential judgement, she talked about problems that which can occur with developing an IGG. However, I don't think any of this would have been brought up if AT didn't have questions about the DNA in this case.
No, I'm saying if Blum was right, there were not enough diploid cells to get a complete STR profile. A partial profile could lead to a false identification. If it was a partial profile, and the identification was false, then the IGG would be wrong, too.
IMO, IF the DNA was partial due to being degraded by sitting on brass, and the ID was made on the partial DNA, THEN, both the STR profile and the IGG developed from the STR profile could be completely wrong. It would all come down to GIGO (Garbage In, Garbage Out.)
Howard Blum wrote that the sample was "20 skin cells (maybe less.)" in Eyes of a Killer, Chapter 4. All the literature I can find online about how many skin cells are needed to get an STR indicates that normally 80 skin cells are needed. The literature also indicates that some of the cells are destroyed in processing. So I have to really wonder how good is the STR in this case? Was it complete or partial?
Just to put into perspective how tiny the sample found on the snap of the sheath was: "A single square inch of skin has about 19 million cells."
Skin Fun Facts | Premier Dermatology
Skin Fun Facts: Did you know…? Your skin is your largest organ and plays a vital role in detecting hot and cold, regulating your body temperature andpdskin.com
"Currently, the optimum DNA input to the PCR for STR profiling is around 500 pg [[1], [2], [3]], which equates to approximately 80 diploid cells (∼6 pg/cell [4]). If the potential of DNA loss through workflow processing is not considered, any item from which 80 cells are collected should generate a full DNA profile."
If Blum is right they collected only 20 diploid cells or less.
"Many laboratories use commercially available STR amplification kits. Depending on the kit and reaction volume, the optimal concentration of input DNA will be in the range of 0.5ng – 2ng. Adding too much or too little DNA to the amplification reaction can result in problems in the analysis."
DNA Extraction and Quantitation for Forensic Analysts | Overview
Current forensic DNA analysis uses polymerase chain reaction (PCR) based short tandem repeat (STR) testingnij.ojp.gov
A further problem with such a minuscule sample is that the entire sample would be used up in the testing process leaving the defense without any option to have another lab run the same testing process on part of the sample to see if the results are identical or not. In this case, we have a prosecutor who initially told the court that they were going to have to "trust them" on the DNA identification. From that point forward he has proceeded to drag his feet about giving the defense any information about the DNA testing process at all. IMO, it's not a good look nor should it be tolerated. A fundamental of the scientific process is the reproducibility of results - that you have to be able to replicate the results to prove if the process worked correctly or not.
Here, the sample is too small to give half of it to the defense, so the next option would be to give complete documentation of the findings and then the defense can run BK's DNA to see if it matches LE's findings.
What is going on in this case is one of the reasons why I don't like non-scientists being in control of scientific evidence. In this case we have one lawyer trying to hide a scientific process from another lawyer and her DNA experts. It is really ridiculous. There should be no reason for that whatsoever. Either the scientific process worked correctly or the results were questionable or it did not work. Regardless of which outcome, it must be completely exposed and examined. Further, the Judge, also a non-scientist, got involved in deciding what parts of a scientific process the defense may view. How would JJ know what is Germaine about the testing? This is certainly not his area of expertise.
IMO, we need to do better. Our court system owes that to all of us.
4 Univ of Idaho Students Murdered, Bryan Kohberger Arrested, Moscow, Nov 2022 #94
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The IGG was an investigative lead, as was CODIS before it.
It gave LE a direction. Better said, it confirmed LE's direction; it wasn't however their basis for arrest.
It's all moot though because LE has two known samples to compare, the DNA from the sheath which was adequate for testing and DNA from BK's mouth. And those are a statistical match, odds of it also matching another living person so high you'd need to multiply earth to find another.
The results of the comparison between the DNA from BK's buccal swab and the DNA from the sheath confirm that genetic genealogy got it right. There's no secret, no conspiracy, no sleight of hand. It's a CODIS database for everyone. Where everyone in those databases necessarily opted in.
AT didn't get a chance to obfuscate at a preliminary hearing so she's trying to do it now. Attack the evidence. Create the spectre of incompetence.
Case in point, challenging the detective on not saving work product. Sounds legit. Point he didn't have any work product outside of what he turned over. Opening a file doesn't require a save! Nor opening emails in search of files so he can locate the file string. No one would save that. There's nothing TO save. In fact, saving a file would give the appearance that something HAD BEEN DONE!
She's trying to build a defense out of nothing.
It shows.
JMO
It gave LE a direction. Better said, it confirmed LE's direction; it wasn't however their basis for arrest.
It's all moot though because LE has two known samples to compare, the DNA from the sheath which was adequate for testing and DNA from BK's mouth. And those are a statistical match, odds of it also matching another living person so high you'd need to multiply earth to find another.
The results of the comparison between the DNA from BK's buccal swab and the DNA from the sheath confirm that genetic genealogy got it right. There's no secret, no conspiracy, no sleight of hand. It's a CODIS database for everyone. Where everyone in those databases necessarily opted in.
AT didn't get a chance to obfuscate at a preliminary hearing so she's trying to do it now. Attack the evidence. Create the spectre of incompetence.
Case in point, challenging the detective on not saving work product. Sounds legit. Point he didn't have any work product outside of what he turned over. Opening a file doesn't require a save! Nor opening emails in search of files so he can locate the file string. No one would save that. There's nothing TO save. In fact, saving a file would give the appearance that something HAD BEEN DONE!
She's trying to build a defense out of nothing.
It shows.
JMO
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So genuine question - Where I'm falling short of understanding how the IGG is not important to the identification of BK, is how did LE determine that it was BK's car out of the approx 22K in the area and the 90 at WSU? i understand identifying the car lead them to the fathers trash. I haven't read absolutely every court document, but there is a gap in the PCA (and everything i've read) about how they actually narrowed the search down (if we are saying they did it entirely without IGG). if BK was "on their short list" without any help of IGG, how?
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Just wanted to thank you for this excellent post!
I had watched the expert testimony & had the same impressions about the testimony. The difference is you have a much better understanding than I do, so I’m grateful to know my “take” was pretty accurate.
Also, I learned from your excellent post — thanks so much for taking time to help me learn more!
Yes, agree--this is exactly what I said above. AT was trying to convince the court that it was essential for her to view the process by which the FBI generated the lead through IGG. The FBI said this was not subject to discovery as the process of IGG is not material to the preparation of his defense. AT was trying to convince the court otherwise.
What questions does AT have about the dna in this case--I'm genuinely asking. What specific questions has she had? Has she specifically had questions about the dna on the sheath matching BK?
Okay, but above you said:
IMO, if AT ONLY thought that LE got the DNA illegally, she would not be asking about any of this at all.
Saying that there's not enough diploid cells to get a complete STR profile is not the same thing as saying AT thinks LE got the DNA illegally.
And this would have nothing to do with the IGG being wrong or right. The profile produced matches. If we didn't have the dna on the sheath a match to BK, there would be room for argument that perhaps one of the other members of the family tree produced by the IGG is the actual contributor of the dna on the sheath. But we do have a match to BK and that hasn't been disputed by the defense.
As I said, if the IGG is wrong, this is very bad for the defense as it's their last ditch effort to get the dna thrown out on a technicality. It would indeed be Garbage Out with all the other leads that didn't pan out and not an issue in the is case.
The defense may try to argue that they need to see the family tree that was created to view others who may be the actual killer. But this is not their true intent. They could easily replicate the IGG done on their own by loading BK's dna into ancestry and compiling their own IGG report, complete with all the other members of the tree. That's not what they're after. They want to see if there were any TOS violations they can use to get it thrown out.
I haven't seen anywhere the defense has said there wasn't enough dna on the sheath for the match to BK. Have they?Howard Blum wrote that the sample was "20 skin cells (maybe less.)" in Eyes of a Killer, Chapter 4. All the literature I can find online about how many skin cells are needed to get an STR indicates that normally 80 skin cells are needed. The literature also indicates that some of the cells are destroyed in processing. So I have to really wonder how good is the STR in this case? Was it complete or partial?
Just to put into perspective how tiny the sample found on the snap of the sheath was: "A single square inch of skin has about 19 million cells."
Skin Fun Facts | Premier Dermatology
Skin Fun Facts: Did you know…? Your skin is your largest organ and plays a vital role in detecting hot and cold, regulating your body temperature andpdskin.com
"Currently, the optimum DNA input to the PCR for STR profiling is around 500 pg [[1], [2], [3]], which equates to approximately 80 diploid cells (∼6 pg/cell [4]). If the potential of DNA loss through workflow processing is not considered, any item from which 80 cells are collected should generate a full DNA profile."
If Blum is right they collected only 20 diploid cells or less.
"Many laboratories use commercially available STR amplification kits. Depending on the kit and reaction volume, the optimal concentration of input DNA will be in the range of 0.5ng – 2ng. Adding too much or too little DNA to the amplification reaction can result in problems in the analysis."
DNA Extraction and Quantitation for Forensic Analysts | Overview
Current forensic DNA analysis uses polymerase chain reaction (PCR) based short tandem repeat (STR) testing
When you say "the dna testing process" you're talking about matching the dna on the sheath to BK? The defense has asked for the dna testing process and the prosecution has said no? The defense has asked to run their own test and the prosecution has said no, there's not enough dna?
The prosecution has not tried to hide a scientific process from another lawyer and her experts. The FBI has claimed the information the defense wants is not material to the preparation of the defense and not subject to discovery. And that is why you need a judge. Because that's a legal question, not a scientific question.
10ofRods
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No. It was not the car that led to the father's trash. It was the IGG. That led to the name Kohberger (a name already on a list back in Pullman, apparently - and yes, they did know that Kohberger had a similar car, IMO, although I'm not sure we have any remaining public documents to drawn on, so IMO).
The car was just the car of a nearby student, one who had not contacted LE about having such a car despite repeated pleas about it. I assume that BK's professor also had some clue about the car and while it's only a hunch, I believe it's possible that some of BK's colleagues may have mentioned him to Pullman LE.
At any rate, it was the IGG that led to the trash, not the car. The timeline shows it in that way.
They did not do it entirely without IGG. They used IGG, that's why AT is in court battling over it.
IMO. He was on the short list, his name showed up in IGG, they went to his dad's house in PA. In addition, they also knew he was in the area (close enough to drive to 1122), that he had a similar car, and that he matched DM"s brief description. But it was the IGG that sent them to PA.
If the IGG had not turned up the name Kohberger (and that name was not already known to LE in WA and ID), this case would have gone differently. Did they use the IGG directly to ID Kohberger? Nope. They used it to justify getting trash from his dad's trash. Which is legal.
IMO.
There's probably only 22k people in Moscow or Pullman (perhaps closer to 26k). That number was, I believe, misreported. Maybe they meant to say 12k in the region? This definitely is inaccurate I'd be surprised if it was 2.2k. This doesn't answer your exact question but it needs to be thought about. JMOO
Hyundai's market across the country is like 5%. This has to be inaccurate. Between the two colleges there's 38k students, many of which don't even have a car. If we guessed 2,200 were Hyundai's that seems far more realistic.
BKs ultimately would have stood out because of a license plate registration change on 11/18 (just 5 days after the murders, suspicious) from a one plate Pennsylvania license to a two plate Washington license. He awaited the new tags from Washington which were apparently issued 12/05. I'm not sure if that gave him a temporary tag precisely but it is a Red Flag. It seems like strategy, to me, to be in license plate limbo. JMOO
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10ofRods
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It is known that DNA degrades when it is on metal surfaces, especially brass. The snap on KBar knife sheaths is made of untreated brass. It is not polished or painted. Further the inside of the snap especially would not have any treatment, even IF it had been treated due to friction from opening and closing the snap.
Brass - Wikipedia
en.wikipedia.org
"The composition of brass, generally 66% copper and 34% zinc"
Zinc, Not Copper, Is the Major Contributor to DNA Degradation and PCR Inhibition in DNA Samples Contaminated with Brass
Limited success in DNA recovery and STR profiling from brass substrates, such as ammunition, has been ascribed to oxidative damage and/or inhibition caused by cpapers.ssrn.com
"Brass showed the strongest inhibitory impact, followed by zinc with copper 10-40 times less inhibitory. Brass and zinc also caused higher DNA degradation than copper. "
"Generating STR profiles from ammunition has traditionally been challenging, resulting in few complete profiles [1], [2], [3], [4]. This is due to the trace amounts of DNAdeposited on the surface of the ammunition [3], [5], as well as the presence of metal ions that can damage the DNA [6] or inhibit its amplification [7]. Studies have demonstrated that ammunition composed of copper alloys, such as brass, adversely affected genotyping success more so than those made of other metals such as aluminum, nickel, or steel [4], [8], [9], [10]. The copper ions can induce conformational changes in the DNA template by intercalating with the strands and causing single and double stranded breaks [11], [12]."
If the sheath was a KBar BRAND sheath, then the DNA was sitting on an untreated brass surface for hours. At minimum it was there from around 4:06am until 12 noon when police were finally called to the scene. We know from the PCA that the ISP CSI was setting up to start processing the crime scene at 4pm on November 13. So it is likely that the DNA was sitting on the untreated brass for at minimum 12 hours. However, I suspect the DNA would have been deposited many hours before the murders if not days. All of this suggests that the DNA sample was degraded.
If it was a small sample of only 20 cells or less, as stated by Howard Blum, AND it was degraded, then it is very likely that the STR may have been partial and the IGG may have identified the wrong person.
You do realize that most of the results involving brass involve either extreme conditions or...decades, more likely centuries?
Brass exposed to sun and rain would have more of an effect (but the inside area of sheath snap would be barely affected). I have pulled DNA off of old brass objects (none more than 120 years old, but still).
Modern labs are well aware of the issue and use different procedures (fairly recent) for recovering DNA from brass objects.
To put it plainly, the DNA isn't degraded much or at all UNTIL it goes into solution with zinc. By creating new solutions that prevent zinc from interacting with the target DNA, the problem is solved (unless the brass and the elements have interacted a lot over decades or centuries).
By understanding how various metals interact with DNA, we are able (in the lab) to use several methods for counteracting its effects (one of which is mentioned in the supporting documents for the PCA, IIRC).
Here are some articles that explain this:
I can give an easier way of visualizing this. We know from the PCA that there was enough DNA to run the STR analysis. What does that tell us? That by looking at all the available DNA from the sheath, they could get enough to do a full STR analysis. I've explained that in past posts, it's too long to go into.
SO, when zinc does interact with DNA, it does so in a random way. Most of DNA is not useful in STR analysis, so what you want is to find enough undamaged STR's to run the analysis for person. The STR's must be intact or there's no point in sending it on to an IGG lab. The forensic lab (in Spokane, I believe) found more than enough STR's - they were able to find evidence of a complete profile. That means, to me, that they had ALL the STR's in use today (there are about 1000 or so - the FBI uses only about 18 because statistically, that's already going to give a really strong identity profile, due again to the sheer improbability of someone having the same alleles (out of 100-1000 alleles available at each of 18 spots. If STR One has 100 variation, then it goes into the formula as 2 to the 100th power (because...we have two alleles at each spot). If STR two has 1000 variations then the odds of people sharing even those two alleles is low - but in families, we do. So we use a bunch more than 2 spots. As I keep saying the FBI uses 18; some sites use 15; Parabon uses a series of complete genes for its analysis, and so on.
There's no way that zinc went in there and erased specific information at the same spot in each of the epithelial samples. It doesn't work that way. Indeed, some of the damage is always to the easiest-to-damage parts of DNA, which is a different topic altogether.
We can think of it as washing dishes. Even with a strong soap and hot water, good forensic analysis can usually and easily turn up cellular evidence of foods cooked in that pan.
IMO.
She is doing anything she can to get away to get away from the straight line from BK to the sheath.
All sideline procedural challenge - no substance.
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Investigators were aware of Kohberger more than a month before his arrest.
On November 29, Daniel Tiengo, a WSU police officer, found a white Hyundai Elantra registered to Kohberger as he searched for vehicles matching the description of one seen near the crime scene.
That information was passed to Corporal Brett Payne, the Moscow police's lead investigator. Payne typed the vehicle's details into the motor vehicles record system and saw that Kohberger's drivers license matched the witnesses' description.
According to this Motion to Compel BK was interviewed by Payne....
As of May 4, 2023, Counsel for Mr Kohberger has not received recordings and notes from the interrogation of Mr Kohberger by MPD Detective Payne.
How Bryan Kohberger's eyebrows helped police link him to Idaho murders
Kohberger is charged with four counts of first-degree murder and one count of felony burglary in connection with the killings of four college students.
www.newsweek.com
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No degrading - nothing wrong with the sheath snap DNA.
An “STR” DNA comparison was performed on DNA collected from Kohberger and DNA taken from the knife sheath, prosecutors said in the June 16 filing. The samples showed a “statistical match,” the court documents state.
An “STR” analysis – or short tandem repeat analysis – is a common type of DNA profiling in criminal cases and other types of forensic cases, according to the National Institute of Justice.
“The STR profile is at least 5.37 octillion times more likely to be seen if (the) Defendant is the source than if an unrelated individual randomly selected from the general population is the source,” prosecutors said in the filing. An octillion is a number equal to a 1 followed by 27 zeros.
The FBI originally loaded the DNA profile from the knife sheath onto publicly available genealogy sites, the documents state.
“The FBI went to work building family trees of the genetic relatives to the suspect DNA left at the crime scene in an attempt to identify the contributor of the unknown DNA,” and then sent a tip to investigate Kohberger, according to prosecutors.
That tip “pointed law enforcement toward (the) Defendant, but it did not provide
law enforcement with substantive evidence of guilt,” according to the prosecutors’ filing – which is why they followed up using an STR analysis.
An “STR” DNA comparison was performed on DNA collected from Kohberger and DNA taken from the knife sheath, prosecutors said in the June 16 filing. The samples showed a “statistical match,” the court documents state.
An “STR” analysis – or short tandem repeat analysis – is a common type of DNA profiling in criminal cases and other types of forensic cases, according to the National Institute of Justice.
“The STR profile is at least 5.37 octillion times more likely to be seen if (the) Defendant is the source than if an unrelated individual randomly selected from the general population is the source,” prosecutors said in the filing. An octillion is a number equal to a 1 followed by 27 zeros.
The FBI originally loaded the DNA profile from the knife sheath onto publicly available genealogy sites, the documents state.
“The FBI went to work building family trees of the genetic relatives to the suspect DNA left at the crime scene in an attempt to identify the contributor of the unknown DNA,” and then sent a tip to investigate Kohberger, according to prosecutors.
That tip “pointed law enforcement toward (the) Defendant, but it did not provide
law enforcement with substantive evidence of guilt,” according to the prosecutors’ filing – which is why they followed up using an STR analysis.
DNA collected from suspect Bryan Kohberger a ‘statistical match’ for DNA on sheath of knife used in killings of 4 Idaho students, court documents state
10ofRods
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<modsnip - quoted post was removed because it didn't contain a link>
Read the full text of the one I first posted. Atomic changes of course take place immediately - but we don't decided that something isn't "human" just because the DNA has "degraded."
There are many other far more perilous journeys taken by DNA. I suggest you read that first article - and then the research on which it is based. It will show you how well calibrated such time scales are.
IOW, if you follow the literature, and read all the citations, you'll see that "an hour" is almost...like a fraction of a second in DNA analysis. Focus on the number of missing base pairs (there is not other measure of "degradation," which is rarely used in the scientific literature). We focus on the actual chemical bonds, their dissolutions and their interactions with...well, you're interested in brass. Follow that trail, but for more up to date science, take a look at zinc (in any context). Then take a look at how forensic LE has incorporated that information.
If I wasn't clear, here's the link.
I mean, it's a legitimate scientific set of questions. And has a long scientific history. But it will only come into the trial if relevant.
And so far, nothing in AT's motions has indicated that she's willing to 1) retest the sample or resubmit it; or 2) challenge the history of DNA collection from a use point that involves brass (because the effects of the zinc are already known and have been incorporated in forensic science for a few years - and are retroactively available for further study).
It won't come up at trial - but if it does, we'll all be glued to our screens.
IMO
Read the full text of the one I first posted. Atomic changes of course take place immediately - but we don't decided that something isn't "human" just because the DNA has "degraded."
There are many other far more perilous journeys taken by DNA. I suggest you read that first article - and then the research on which it is based. It will show you how well calibrated such time scales are.
IOW, if you follow the literature, and read all the citations, you'll see that "an hour" is almost...like a fraction of a second in DNA analysis. Focus on the number of missing base pairs (there is not other measure of "degradation," which is rarely used in the scientific literature). We focus on the actual chemical bonds, their dissolutions and their interactions with...well, you're interested in brass. Follow that trail, but for more up to date science, take a look at zinc (in any context). Then take a look at how forensic LE has incorporated that information.
If I wasn't clear, here's the link.
I mean, it's a legitimate scientific set of questions. And has a long scientific history. But it will only come into the trial if relevant.
And so far, nothing in AT's motions has indicated that she's willing to 1) retest the sample or resubmit it; or 2) challenge the history of DNA collection from a use point that involves brass (because the effects of the zinc are already known and have been incorporated in forensic science for a few years - and are retroactively available for further study).
It won't come up at trial - but if it does, we'll all be glued to our screens.
IMO
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Here's where I have a problem with this. BK did NOT match DM's description. She said the man was 5'10" or taller with bushy eyebrows. BK is 6'. IMO, compared to at least 50% of men, BK's eyebrows are about average. Not extremely bushy, not thin or sparse just kind of average. What I don't see in the PCA is evidence of a photo lineup or actual physical lineup where DM identified the man she saw. Brett Payne did not see the man DM saw, so he is in no way qualified to identify BK yet that is the method of identification in the PCA. That's just not a legal identification by any stretch of the imagination. What is needed would be for DM to identify the man she saw. It will be hard since she apparently only saw stature and eyebrows. Seems like she didn't know stuff like hair color, eye color, race, skin tone, etc. The PCA doesn't say the man had dark eyebrows and there's no description of his eyes or even his approximate age. But DM would be the ONLY person who can identify the suspect and it appears that still had not happened prior to arrest. If DM has not said, "Yes, that is the man I saw, " we basically have zero identification of the man she saw. I wonder if this will go to court and DM will be asked to point out the suspect and she just won't be able to identify him because she is not 100% certain. It is a death penalty case and I'm sure she would want to be absolutely certain and not point out the wrong person as that would weigh on her conscience for the rest of her life. But this really makes me question what the police were doing. Why no lineup? That's standard in a case where there is an eye witness. This makes no sense.
How can it be that defense was not given the recordings and notes from Payne's interview with BK as of May 4, 2023? Are they lost on someone's laptop at MPD? Where are these materials normally stored? Is there no case file retention system???? Has BT even asked Payne where these materials are? Again this makes no sense.According to this Motion to Compel BK was interviewed by Payne....
As of May 4, 2023, Counsel for Mr Kohberger has not received recordings and notes from the interrogation of Mr Kohberger by MPD Detective Payne.
How Bryan Kohberger's eyebrows helped police link him to Idaho murders
Kohberger is charged with four counts of first-degree murder and one count of felony burglary in connection with the killings of four college students.
arielilane
Justice for Liz Barraza
@LawCrimeNetwork
A Moscow police detective testified at a hearing about information he received from the FBI about Bryan Kohberger's cell phone records. Law&Crime's Angenette Levy @angenette5 breaks down Detective Lawrence Mowery's testimony and what it means in this episode of Crime Fix.
A Moscow police detective testified at a hearing about information he received from the FBI about Bryan Kohberger's cell phone records. Law&Crime's Angenette Levy @angenette5 breaks down Detective Lawrence Mowery's testimony and what it means in this episode of Crime Fix.
She des
DMs Description was good, and does not exclude BK.
As someone who does this kind of DNA testing, I can tell you that the “optimal DNA input” is different than the DNA input required to obtain an interpretable profile. Laboratories ask and answer exactly this question in the validation studies they perform prior to implementing DNA testing and DNA profile interpretation procedures. Sensitivity testing during validation of the methods is a requirement for laboratory accreditation.Dr. Larkin wasn't talking specifically about BK because they did not have any DNA evidence to examine at the time. She WAS talking about possibilities that could happen from the processing of DNA and why it was necessary for the defense to be able to examine the evidence. She also spoke about how relationships are determined in IGG which is a combination of science and also experiential judgement, she talked about problems that which can occur with developing an IGG. However, I don't think any of this would have been brought up if AT didn't have questions about the DNA in this case.
No, I'm saying if Blum was right, there were not enough diploid cells to get a complete STR profile. A partial profile could lead to a false identification. If it was a partial profile, and the identification was false, then the IGG would be wrong, too.
IMO, IF the DNA was partial due to being degraded by sitting on brass, and the ID was made on the partial DNA, THEN, both the STR profile and the IGG developed from the STR profile could be completely wrong. It would all come down to GIGO (Garbage In, Garbage Out.)
Howard Blum wrote that the sample was "20 skin cells (maybe less.)" in Eyes of a Killer, Chapter 4. All the literature I can find online about how many skin cells are needed to get an STR indicates that normally 80 skin cells are needed. The literature also indicates that some of the cells are destroyed in processing. So I have to really wonder how good is the STR in this case? Was it complete or partial?
Just to put into perspective how tiny the sample found on the snap of the sheath was: "A single square inch of skin has about 19 million cells."
Skin Fun Facts | Premier Dermatology
Skin Fun Facts: Did you know…? Your skin is your largest organ and plays a vital role in detecting hot and cold, regulating your body temperature andpdskin.com
"Currently, the optimum DNA input to the PCR for STR profiling is around 500 pg [[1], [2], [3]], which equates to approximately 80 diploid cells (∼6 pg/cell [4]). If the potential of DNA loss through workflow processing is not considered, any item from which 80 cells are collected should generate a full DNA profile."
If Blum is right they collected only 20 diploid cells or less.
"Many laboratories use commercially available STR amplification kits. Depending on the kit and reaction volume, the optimal concentration of input DNA will be in the range of 0.5ng – 2ng. Adding too much or too little DNA to the amplification reaction can result in problems in the analysis."
DNA Extraction and Quantitation for Forensic Analysts | Overview
Current forensic DNA analysis uses polymerase chain reaction (PCR) based short tandem repeat (STR) testing
A further problem with such a minuscule sample is that the entire sample would be used up in the testing process leaving the defense without any option to have another lab run the same testing process on part of the sample to see if the results are identical or not. In this case, we have a prosecutor who initially told the court that they were going to have to "trust them" on the DNA identification. From that point forward he has proceeded to drag his feet about giving the defense any information about the DNA testing process at all. IMO, it's not a good look nor should it be tolerated. A fundamental of the scientific process is the reproducibility of results - that you have to be able to replicate the results to prove if the process worked correctly or not.
Here, the sample is too small to give half of it to the defense, so the next option would be to give complete documentation of the findings and then the defense can run BK's DNA to see if it matches LE's findings.
What is going on in this case is one of the reasons why I don't like non-scientists being in control of scientific evidence. In this case we have one lawyer trying to hide a scientific process from another lawyer and her DNA experts. It is really ridiculous. There should be no reason for that whatsoever. Either the scientific process worked correctly or the results were questionable or it did not work. Regardless of which outcome, it must be completely exposed and examined. Further, the Judge, also a non-scientist, got involved in deciding what parts of a scientific process the defense may view. How would JJ know what is Germaine about the testing? This is certainly not his area of expertise.
IMO, we need to do better. Our court system owes that to all of us.
From my experience, approximately 20 cells worth of DNA (which is equivalent to about 120 picograms) can be enough to obtain a complete STR profile. If that was the DNA input utilized in the testing in this case, my guess is that either a full profile or a high partial profile was obtained. An STR profile need not be complete to be informative - a high partial profile can still produce very informative statistics. I don’t know how much DNA was available or used for the IGG testing (production of the SNP profile), but if it wasn’t substantially higher than 120 pg, then whole genome sequencing was very likely the method utilized.
As to degradation… there are differing degrees of DNA degradation, multiple methods for assessing whether or not it is present, and it may or may not impact the DNA testing results. I have no direct knowledge of the Idaho lab’s procedures, but my guess is that the DNA quantitation method they performed (prior to STR typing) included an assessment of DNA degradation; and if this was the case, they would have some indication going into the STR typing whether or not the DNA was degraded. Further, when DNA degradation is present, it can often be observed in the DNA profile (the classic “ski slope” effect in capillary electrophoresis-based STR profiles). The fact that an STR profile was obtained indicates that at least some of the DNA present in the sample was relatively intact, as the STR target regions are generally 100-400 base pairs in length. It is also worth noting that if the Idaho lab used one of the most common interpretation software packages (STRmix) to generate their statistic, then any degradation apparent in the STR profile would be taken into account in the generation of the stat. As to the IGG testing, if the method used was whole genome sequencing, then degradation is far less of a factor than it is with STR typing. With IGG, single SNPs are the target, and fragments as small as around 30 base pairs can be sequenced. If an STR profile can be obtained, the DNA is certainly intact enough for IGG via whole genome sequencing.
All my opinion only.
A partial, degraded, str dna 'profile' extracted from use button of sheath? Speculated off of what known facts in the case I wouldn't know. A credible 'what if' scenario? Not from what I've read in court docs and according to those with knowledge who post here. Even if I found Blum minutely credible, all I see is circular what if speculation but we're all entititled to our opinons ofcourse. Jmo
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Are today's hearing still on schedule? 10 am PST - Motion to Compel Open
3 pm PST - IGG Motion to Compel Closed
Thanks
3 pm PST - IGG Motion to Compel Closed
Thanks
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