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Larry Ray Swearingen

I think I read somewhere (forgot to bookmark it) that the DNA profile from the blood was tested against some people identified by the defense (presumably possible alternative suspects) but didn't match. It was also mentioned that the prosecution came up with theories at some point (not sure if this was during appeal or original trial) about how it could have resulted from contamination. It would have thought it straightforward to identify individuals who were potential sources based on the prosecution theory, but I haven't seen anything yet suggesting this.
 
Who were these individuals?

"Subsequent DNA testing of the flakes yielded a single- source DNA profile that was inconsistent with the individuals in the case, including Swearingen. 30 RR 127. She further testified that, “ It’s a very, very tiny sample. And for something that small to type as well, to do a full profile on it, it would tend to indicate to me it was a very well preserved, fresh blood sample that really has not been exposed to the elements.” 30 RR 127." p. 20 of this document. (I note in passing that this document specifically mentions AEDPA). I would like to know more about who was eliminated as a donor of this DNA.

Nurit B et al., Forensic Science International: Genetics 5 (2011) 532–537. "These studies provided the evidential value of the low background level of DNA mixtures within the general population, leading to the inevitable conclusion that the cellular debris accumulated under one’s fingernails throughout routine casual activities, is not consistent with DNA mixtures, and particularly not high level or reportable type of mixtures. Results of this study show that the prevalence of DNA mixtures found among murder victims fingernail samples, is much higher: 25% of the victims’ samples genotyped provided additional alleles other than the self component."

If contamination of fingernail DNA evidence were a common occurrence, its evidentiary value would be quite low. Yet according to the prosecution, it happened in this case.
 
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Chris_Halkides said:
"Rytting said the pantyhose matching is an example of “quackery,” and said the pieces did not match at first but were “pushed and pulled” until they did. Blackburn emphasized though that Mills’ letter didn’t contradict the original testimony, and said the two pieces of fabric were an easy match." Texas Tribune.

"A second letter from Mills, however, stated a DPS witness should have given a “more appropriate answer” regarding blood flecks found on Trotter’s fingernails after they were submitted to the agency. The lab analyst at trial [Cassie Carridine?] said the blood, which Blackburn said amounted to a the size of a pinpoint, possibly came from contamination in the lab — not the crime scene. She said this was because the brighter color and composition of the blood indicated it was from after her death." Texas Tribune

"[Lab Director Brady] Mills also has conceded that Texas lab serology expert Cassie Carradine—who later was implicated in mismanagement of the Austin police crime lab—provided inaccurate testimony at trial about blood evidence that appeared to exclude Swearingen as the killer. Blood flakes found under Trotter’s fingernails were subjected to DNA testing and revealed a DNA profile of an unidentified male who was not Swearingen. Carradine incorrectly testified that because the flakes were “bright red,” they couldn’t have been under the victim’s fingernails, and must have come from contamination “either at the time the sample was being collected” at autopsy “or after the sample was being collected,” rather than from a physical struggle between Trotter and her killer. Mills said that Carradine “had no direct knowledge about how the evidence in question was collected or stored prior to its submission." Death Penalty Info

"Blood flakes were found under Trotter’s fingernails, enough to develop a full DNA profile, which was determined to be from a man — but not Swearingen. But a Texas lab technician testified at trial that the blood came from contamination in the lab, not a possible killer. Earlier this month, the Texas Department of Public Safety issued a second letter saying the technician had no evidence of contamination or knowledge of how that would have happened." WaPo

Pathologist Joy E. Carter, M.D., apparently supported Ms. Carradine. See pp. 20-23 of this link, which is from the respondent (The State of Texas IIUC).

It has been said that dried flakes are a greater contamination hazard than wet blood. Yet wouldn't a laboratory have air handling designed to minimize this possibility? I don't know of any good citations on the idea of dating the blood from the color, but I am highly skeptical (it is subjective at best, and it has no support from the forensic literature of which I am aware). A good DNA lab has a staff elimination file to check for laboratory personnel.

EDT
I have long been troubled by this case. Yet until having examined it a little more carefully as part of this thread, I did not realize how slipshod the forensic analyses were.
Click to expand...

There is a well documented case of contamination of the DNA from nails, it was identified as being due to inadequate cleaning of the nail clippers. The laboratory responsible recognised the issue and published to alert others to the issue.

An interesting issue is the assumption by the reporting scientist of the prosecution case in interpreting the DNA. She thought the DNA was contamination because it was in two good a state to fit with the prosecution time line. (As it appears was the case with the victim's body which appeared well preserved for the prosecution time line.) The correct report would have been that the DNA found indicated that either the time line suggested by the prosecution was incorrect, or this was in-laboratory contamination. (I assume this then raised issues about all other DNA evidence tested in other cases by this laboratory?)

This unconscious bias (or sometimes conscious bias) is something that professional forensic scientists need to guard against, all too often they are perceived as being part of the police / prosecution instead of being neutral. In the UK such testimony is required to be delivered as an 'agent of the court' not as a prosecution or defence witness.
 
Peter Gill on fingernail DNA

Peter Gill's invaluable book discusses fingernail DNA on pp. 67-80, and he summarizes much of the literature up to 2014. One thing that I did not emphasize previously is that this fingernail sample is source, not sub-source, DNA, although the association between a body fluid and a DNA sample is not "implicit," meaning that the connection is not automatic and absolute.

It is difficult to infer how old a DNA profile is because the rate of DNA degradation is subject to many variables. My issue with the lab is that they made an inference that has no grounding in experimental results of which I am aware. My reading of Professor's Gill's passage is that the job of the forensic scientist is to make the court aware of all possibilities.

There are a number of wrongful convictions in which fingernail DNA was found not to be from the person originally convicted.
 
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Just glancing over the links to appeals, it looks as though the prosecution attitude was 'we have a good case based on circumstantial evidence, so why bother with exculpatory evidence'?

Or perhaps I should say that was the appeals court attitude.
 
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Fingernail DNA in the cases of Malcolm Bryant, Chad Heins, and Anthony Johnson

I would offer the cases of Malcolm Bryant, Chad Heins, and Anthony Johnson as some of the better examples of the use of fingernail DNA evidence to correct a wrongful conviction. Yet in this case the prosecution and forensic workers made the astonishing claim that a fleck of blood happened to contaminate this sample.
 
"In addition to Carter five other experts – two forensic entomologists and three forensic pathologists – have independently provided affidavits attesting to when Ms. Trotter’s body was placed in the forest." Justice Denied

I keep coming back to the pubic hair that was not from Mr. Swearingen. Is this another example of an "unindicted co-ejaculator?" See this link for a little bit of discussion of unindicted co-ejaculators and cognitive dissonance.
 
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From the Dublin Review article cited above, "It was revealed at trial that on two separate occasions in the fortnight before the corpse was discovered, search teams with cadaver dogs had passed within twenty metres and found nothing."
 
I decided to provide a short summary of this case. I have a difficult time seeing how Ms. Trotter's body could have been left where it was found for more than three days. If that is so, then Larry Swearingen had been incarcerated for about two and a half weeks.
 
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