Yea!!...so if they have that root hair now (with tissue attached) why are the "experts" saying they may not even get a complete tox analysis back?
Somewhat seperate issue from DNA - Dr G seemed to think there was no tissue left - meaning that they are probably relying on the hair strand itself to give up information if drugs were excreted into the hair as it grew (a common example of this type of testing is for cocaine - I have a friend who did a chemistry thesis on this exact test). It doesn't sound like the skeleton had hair roots either (they decompose as they are normal tissue). From the reports, the nuclear DNA id was made on bone (not always a successful process either, as seem in museum studies of bone). I am not sure if there is bone marrow or anything other than bone and hair to do tox tests on because I am not sure what falls into the "no tissue left" category.
The problem for "complete" results to come back is complex. First, if there was a one-time "poisoning" (including drug use) just prior to death, the body would not have time to excrete drug signatures into the hair or elsewhere, so that evidence would be gone with soft tissues. Second, even if there had been a history of poisoning allowing for excretion, there isn't an easy way to turn this into a timeline. That allows for plenty of opportunity to explain it away - "I don't know how my kid got this drug", "I don't know when it happened" etc - so that it may not be a clear tie to death. Third, the drug or poison may be one that does not show up in the tissues remaining. I still question, despite seeing people state otherwise, if chloroform would show up in hair. I just can't yet find the journal article to back it up.
So, whatever comes back won't help a ton - if it comes back clear, then we can't rule out a close to death overdose or a drug that doesn't leave a signature in hair/bone. If it doesn't come back clear, there could be harmless explanations posited by the defense, or at least arguments that they can't be attributed to death.
I took my forensic tox classes several years ago, so this could be wrong in the details. End result is that it can't possibly hurt to get the tox results back as the worst case scenario is that they show nothing, which
doesn't rule out murder by overdose.
HTH.