Ed. Note: Chris Halkides has been kind enough to try to make us lawyers smarter by dumbing down science enough that we have a small chance of understanding how it’s being used to wrongfully convict and, in some cases, execute defendants. Chris graduated from the University of Wisconsin-Madison with a Ph.D. in biochemistry, and teaches biochemistry, organic chemistry, and forensic chemistry at the University of North Carolina, Wilmington.

Larry Swearingen was his own worst enemy. He had repeatedly been in trouble with the law; there are reports that he was violent toward women. He may have denied knowing the murder victim, Melissa Trotter, to the police, despite their being friends (possibly with benefits). When imprisoned, he dictated a letter that claimed to be authored by someone else who had knowledge of the crime in a strange attempt to divert suspicion from himself. Those prevarications don’t make him guilty. Yet despite more than one robust line of evidence indicating that he was innocent, the State of Texas executed him in August of 2019.

Melissa Trotter disappeared on 8 December 1998, and her body was found on 2 January 1999 in the Sam Huston National Forest. She had been strangled with one leg of panty hose. A portion of panty hose was found during a warrantless search, after his trailer had been searched at least twice. A forensic examiner, Sandi Musialowski, testified that the two lengths of hose matched “to the exclusion of all other pantyhose.” Yet, pantyhose is elastic. This is vaguely reminiscent of one of the problems in the Lindy Chamberlain case.

It is equally problematic that Musialowski had initially found no match. Textile expert Max Houck wrote in an affidavit, “It is not possible to check these exhibits against all other possible targets.” The Death Penalty Information Center wrote:

“Deborah Young, a professor of textile science at Cal Poly Pomona, wrote that “[a]t first glance” the pieces of fabric from the ligature and the pantyhose “appear to connect, but once the deliberate space between them is removed, it becomes quite clear that they do not match … My opinion is that while both pantyhose were cut in the same basic silhouette, they were not cut from the same piece. These are not a match, and certainly not to ‘the exclusion of all other pantyhose.’”

Polyester fibers claimed to be from his truck were found on Ms. Trotter’s coat. Yet identifying a fiber as being polyester provides only a class characteristic, not an individualizing characteristic. Even if the fibers matched, the friendship between the two is an innocent explanation.

Blood and DNA underneath the fingernails of a murder victim is highly probative, because foreign DNA under one’s fingernails does not persist when one is alive, and the identification of blood as the probable source raises its probative value above unsourced DNA. In his book Misleading DNA Evidence, DNA expert Peter Gill wrote, “certainly the presence of blood underneath fingernails in conjunction with a major foreign [DNA] component must be a significant finding.”

The Malcolm Jabbar Bryant, Chad Heins, and Anthony Yarbough exonerations relied upon fingernail DNA. In the Yarbough case, the DNA profile was linked to another murder. In the Heins case, DNA from the fingernails was consistent with DNA from hair and from a semen stain. In the Bryant case, a stained t-shirt produced a profile consistent with the one arising from the fingernail. When DNA from the fingernails is connected with other evidence at the crime scene or elsewhere, the sum becomes even more persuasive. One limitation in the DNA analysis of hairs is that sometimes only mitochondrial, not autosomal, DNA is obtained.

How did the state respond to the blood beneath Ms. Trotter’s fingernail? Jordan Smith wrote,

To explain that away, the state offered several theories — one of the cops present at the autopsy might have cut himself shaving that morning and the blood somehow wound up under Trotter’s nails; or maybe the blood of an investigator was blown under her nails by the whirring blades of a helicopter searching the forest for her body.

Forensic scientist Cassie Carradine claimed that the bright color of the blood speck indicated that it came from recent laboratory contamination. This is a subjective and unsupported means of dating a body fluid. The Texas Department of Public Safety later conceded that this was erroneous testimony.

Pubic hairs that were not Swearingen’s (one surmises that this was shown by microscopic examination) are substantial pieces of evidence pointing away from Swearingen as the true culprit. The rape kit was not, as of October of 2015, tested for DNA, nor were hairs found on or near her body.

The 2015 appeal judgment referred to the “mountain of evidence” against Mr. Swearingen. Yet the time of death was the prosecution’s mountain. Swearingen was taken into custody on 11 December 1998, initially for speeding tickets, then later on charges relating to this crime. Cadaver dogs had twice passed within twenty meters of where her body was found. One entomologist stated that the maggots could have begun their decomposition of her body no earlier than 18 December. The location of maggot infestation on the body and the lack of predation of the body by birds and omnivorous wild pigs led another entomologist to conclude that Ms. Trotter’s body had been in its location for no more than one week (no earlier than December 26).

A third expert, the medical examiner for Harris County, thought that the body had been in the forest for no more than two weeks, based upon lack of skin slippage and other factors. In addition, her internal organs were still partially intact and were sectioned, yet the pancreas begins to liquify within days. The appearance of her heart suggested that she was recently deceased. Her body weight was close to what it had been when she was alive. Even the original medical examiner, Joye Carter, revised her opinion that Ms. Trotter had been dead the whole time that she was missing, later concluding that Ms. Trotter’s body had been in the forest for less than two weeks.

The various testimonies placed Melissa Trotter’s body in the woods between two and fourteen days prior to its discovery. The failure of the cadaver dogs to find her body, the condition of the internal organs, and the lack of bloating suggest that the body had been left in the woods for two or three days before discovery. If, however, the body had been left two weeks (19 December), Swearingen had already been incarcerated for about eight days.

Ms. Trotter had received threatening phone calls, which were not from Mr. Swearingen. An alternative to the state’s hypothesis is that this person abducted and imprisoned Ms. Trotter, possibly in another state, given that the type of blow fly was not common in Texas: she was killed a few days before her body was returned to the area and placed in the forest. The investigation was rife with tunnel vision and dubious forensic testimony.