There is plenty of reason to suspect there is no DNA. First off Shirley was in the water for 10 days so that rules dna out on her remains.
Secondly DNA does reveal the gender/ethnicity of the suspect (even though that is rarely discussed because it isn't PC).
If they had DNA I think Sills would have come out with a bit more info on a possible POI that they wanted to talk to, such as a white/black/hispanic male that may have been in the area that day based on the mystery dna markers (modsnip)
Yes, Sonya610, although Sills didn't specify dna, he said that there is forensics and other evidence that will tie a suspect to the crime once apprehended.
Imo, Sills is likely focused on AA perps in the Dermond murders investigation for multiple reasons.. Concerning the determination of the ethnicity of a perp/s using dna forensics. Derrick Todd Lee; the Baton Rouge Serial Killer, comes to mind.
http://en.wikipedia.org/wiki/Derrick_Todd_Lee
Lee was linked by DNA to the deaths of seven women in the Baton Rouge and Lafayette areas in Louisiana, and in 2004 was convicted of the murders of Geralyn DeSoto and Charlotte Murray Pace. Newspapers have suggested Lee can be linked to other unsolved murders in the area, but the police lacked DNA evidence to prove these connections. After Lee's arrest, it was discovered that another serial killer, Sean Vincent Gillis, was operating in the Baton Rouge area during the same time as Lee.
Two of the victims' bodies were discovered at the Whiskey Bay boat launch, approximately 30 miles west of Baton Rouge, just off Interstate 10.
Because the majority of publicized serial killers are white, and based on erroneous eyewitness accounts, police originally believed the killer to be white. Police therefore administered thousands of DNA tests to Caucasian men in and around the general area of the murders.
Having no leads, police then allowed DNAPrint Genomics access to DNA left at the crime scenes. DNAPrint Genomics generated an ancestry profile indicating that the suspect was 85% African,[2] thus changing the course of the investigation: Police now knew they were searching for a black man for the January 2002 slaying of Geralyn Barr DeSoto. More specific analysis of the DNA evidence found under the fingernails of DeSoto linked Lee to the 21-year-old Addis, Louisiana womans death.
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May 5, 2015
Person of interest identified in murder, beheading of elderly couple
http://www.wsbtv.com/news/news/local/exclusive-sheriff-has-person-interest-murder-behea/nk9M3/
Tuesday, Sills confirmed exclusively to Winne that he has a person of interest in the case.
He told Winne the person of interest is someone theyve interviewed before.
Statements made to us, we later determined, were not completely truthful, Sills said.
Sills says he doesnt have enough so far to elevate the person of interest to an official suspect and investigators still do not have a motive for the murders.
Sills says its a case that weighs on his mind every day.
Theyre still out there and by God, theyre capable of doing anything, Sills said.
Sills says he recently re-interviewed a close relative.
I took a firmer tone this time. This person kind of broke down. After it was over with, my personal thoughts are that she certainly didnt have anything to do with it, but I never say never, Sills told Winne.
He says when they do, they have both physical and forensic evidence to compare to that person.