Kosoul Chanthakoummane Faces Execution in Texas Despite Lack of Evidence of Guilt


By Ariel Peterson


AUSTIN, TX—Kosoul Chanthakoummane is scheduled to be executed in Texas on Aug. 17, 2022, despite significant doubt with his conviction due to its reliance on faulty and insufficient evidence.


Chanthakoummane was first found guilty of the murder of McKinney, Texas, real estate agent Sarah Walker in 2007.


Walker’s body, discovered in the kitchen of a model home by a house-hunting couple, was a gruesome sight. She had been stabbed 33 times, her nose and teeth were broken, her Rolex watch and wedding ring were missing and, significantly, she had been bitten by her attacker on her neck.


The only eyewitnesses were another realtor and her husband, who had been at the model home the morning of Walker’s murder and had mistaken a man they saw outside the home for a potential client.


Both eyewitnesses subsequently underwent hypnosis performed by Texas Ranger Richard Shing, after which a composite sketch of the suspect was produced.


This composite sketch led McKinney police to Chanthakoummane, and after finding DNA evidence that linked him to the model house, McKinney police concluded in an Associated Press article that they were “confident in their arrest.”


Chanthakoummane’s trial began on Oct. 8, 2007, and on Oct. 17, 2007, a jury found him guilty of capital murder.


Nevertheless, Chanthakoummane has always asserted that he is actually innocent.


In the years since, scientific developments have cast doubt on much of the evidence that was crucial to Chanthakoummane’s conviction.


First, there was the bitemark evidence.


Dr. Brent Hutson had been called to testify in Chanthakoummane’s case after performing an analysis of the bitemark on Walker’s neck. After taking molds of both the bitemark and Chanthakoummane’s teeth, Hutson told the court it was his opinion “within dental certainty, that the teeth of the suspect were responsible for that patterned injury.”


Hutson also testified, though, that he “did not even make an attempt to make any other blind comparisons of dental impressions,” according to Chanthakoummane’s most recent application for writ of habeas corpus, and therefore he couldn’t say Chanthakoummane was “the one and only person in the world that could have caused this injury.”


Furthermore, bitemark evidence has more recently been debunked and is now considered junk science. 


As Chanthakoummane’s habeas application notes, a 2009 report by the National Academy of Sciences found that “there is an inadequate scientific basis for concluding that ‘bitemark comparisons’ can cause a ‘conclusive match.’” 


His lawyers also state that “attorneys and scientists have exposed bitemark-identification evidence as a leading cause of wrongful convictions” and “Texas courts no longer accept bitemark analysis as a reliable scientific discipline.”


A similar story is true for the hypnosis techniques used to elicit eyewitness testimony. 


The witnesses had been instructed to visualize the events of the day they were at the model house in their “mind’s eye” as if their minds could capture pictures and video objectively, like cameras. Research in cognitive psychology has revealed, though, that this is an inaccurate assumption about how memories work.


Chanthakoummane’s habeas application includes statements from a consultation with psychology professor Dr. Steven Lynn, who declared, “The vagaries of memory contradict the view that memories are stored in pristine form; it is now widely recognized that what is recalled is rarely if ever, a true ‘snapshot’ of a witnessed event.”


Dr. Lynn gave another explanation as to why memories accessed under hypnosis may not be accurate: “Non-hypnotic suggestive procedures can implant false memories of complex events, such as riding in a hot air balloon, being the victim of bullying, being subjected to a vicious animal attack, and committing a crime, in approximately 20% to 80% of participants.”


Thus, anything the McKinney police or Texas Rangers might have suggested to the two witnesses about the suspect they were looking for may have informed their recollections under hypnosis, rendering their testimony unreliable. 


Yet even after undergoing hypnosis, the two witnesses’ descriptions of the man they saw remained vague. Both described the man as being of Asian descent and wearing a sleeveless shirt, but neither mentioned any more specific identifying characteristics, like the glasses Chanthakoummane would have been wearing or the tattoo sleeve that would have been visible if he was wearing a sleeveless shirt.


Even the DNA evidence has come under scrutiny since Chanthakoummane’s conviction. 


The Texas Department of Public Safety has admitted that its methods of analyzing the DNA samples from the model home have been discredited and were flawed science, which may have affected how much DNA evidence found at the crime scene could actually be connected to Chanthakoummane.


Abraham Bonowitz and his colleagues at Death Penalty Action raised further questions about the DNA in a letter to the Texas Board of Pardons and Paroles


The case against Chanthakoummane relied on his DNA being found under Walker’s fingernails, yet Bonowitz notes that there is no evidence Chanthakoummane ever received any injury that might have been caused by a struggle with Walker. 


Additionally, Chanthakoummane’s DNA was never found on the plant stand that was reportedly used to hit Walker, and Walker’s DNA was never found anywhere on Chanthakoummane’s person or in his car. 


These inconsistencies led Bonowitz and colleagues to write, “It’s difficult to believe a murder that bloody was committed and the killer left without a drop of DNA to tie the crime to him.”


A final question concerns the theory of the case.


McKinney police stated that “the ferociousness of the attack suggested Walker knew her attacker,” and the Associated Press article quotes Walker’s sister as saying, “We knew eventually this day would come, we just didn’t know when.”


However, police were never able to establish a personal connection between Walker and Chanthakoummane, nor a motive for the murder.


Walker’s father, Joseph Walker, pointed to another person for whom a motive was more likely to exist: Walker’s ex-husband, Randy Tate.


Bonowitz and colleagues received information that Tate and Walker may have had a history of domestic disputes, and the Death Penalty Action team have followed up by filing a Public Information Act request with the Frisco Police Department to investigate whether records of such a history exist.


Regardless, Tate was never a suspect in the case.


Aside from all of the faulty evidence, Chanthakoummane received ineffective assistance of counsel at trial. His original lawyers indicated he was guilty during their opening statements, even though Chanthakoummane insisted he was innocent. His habeas application also mentions that his lawyers “called no witnesses during the hearing to rebut Mr. Shing’s hypnosis practice and procedures; nor did they cross-examine any of the identification witnesses during the trial.” 


The looming Aug. 17 execution date was Chanthakoummane’s second; his original execution was set for Jan. 25, 2017, but he received a stay from the Texas Court of Criminal Appeals instructing the trial court to review his claims about the forensic evidence. 


Now, Walker’s surviving family, Death Penalty Action, and others like them hope for a stay of execution and a new trial with better representation for Chanthakoummane.


Only Kosoul Chanthakoummane himself knows whether or not he killed Sarah Walker. But with so little remaining credible evidence, it would be difficult to determine whether he is guilty beyond reasonable doubt, let alone deserving of the death penalty.


Update as of Aug. 18: Kosoul Chanthakoummane was executed by the state of Texas on August 17, 2022.

About The Author

Ariel Peterson is a second-year Political Science major and English minor at UCLA. After graduation, she is excited to attend law school. She intends on becoming a public interest lawyer to fight injustice in the criminal justice system and help people whose lives have been negatively impacted by the law.

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