Dallas District Attorney and Innocence Project Move to Reverse Conviction Based on False Bite Mark Testimony


(Photo: Lara Solt)

(Photo: Lara Solt)

Steven Mark Chaney walked out of a Dallas courtroom this afternoon after a court reversed his 1987 murder conviction because of discredited bite mark testimony.  Dallas District Attorney Susan Hawk joined the Innocence Project and the Dallas Public Defender’s Office in seeking Chaney’s release. Chaney’s release follows a decision by the Texas Forensic Science Commission to review the use of bite mark testimony in the state.

“After a thorough review of Mr. Chaney’s case led by Patricia Cummings and our conviction integrity unit, we have concluded that the bite mark evidence that was critical in his conviction has been discredited, and it’s our obligation to move to set aside his conviction,” said District Attorney Susan Hawk.  “When we’re relying on science in prosecutions like this, it’s critical that we continue to apply the newest standards, and when these standards change, we review and reconsider these cases. The Texas Forensic Science Commission is currently reviewing the use of bite mark analysis in criminal prosecutions, and will be reviewing other cases where this forensic practice could have resulted in other wrongful convictions.”

“By concluding that this conviction rested on improper forensic testimony and moving to restore justice to Mr. Chaney, District Attorney Hawk has demonstrated that Dallas continues to set the bar for conviction integrity units across the nation,” said Barry Scheck, Co-Director of the Innocence Project. “We have been tremendously impressed by District Attorney Hawk’s commitment to the conviction integrity process.  Prosecutors in the unit, Patricia Cummings and Cynthia Garza, spent hundreds of hours reinvestigating this case in a rigorous, fair and tough-minded way. ”

Chaney was convicted of the murder of John Sweek, based largely on the testimony of two forensic dentists who claimed that Chaney’s teeth matched to a mark on Sweek’s body.  Sweek and his wife, Sally, were found dead on June 20, 1987 at approximately 11 PM in their apartment where John sold cocaine.  Police initially suspected that the couple was murdered by Sweek’s drug supplier after learning from family members that he had threatened to kill the couple before for failing to settle their debts.  Police followed this lead until they received a tip from an informant who suggested that Chaney may have been involved because he owed the couple $500 for drugs. After receiving the tip, police shifted their focus to Chaney, who had purchased drugs from the couple on numerous occasions with the informant.

At trial, the prosecution presented a number of witnesses to back up the informant’s vague suspicions about Chaney’s involvement.   In addition to the informant, a fingerprint analyst testified that Chaney’s fingerprint was found in the home (that the defendant readily admits he visited on multiple occasions).  A serologist claimed that the shoes that he was wearing a month after the murders tested presumptively positive for blood, but she acknowledged that there wasn’t enough substance to even confirm that it was in fact blood and that other substances react positively to the test.

The lynchpin of the prosecution’s case was the testimony of two forensic dentists, Drs. James Hales and Homer Campbell, who each claimed that Chaney’s teeth matched to an alleged bite mark on Sweek’s forearm.  Dr. Hales claimed that there was a “[o]ne to a million” chance that someone other than Chaney could have left the bite mark, a statistic he claimed was in the “scientific literature.”  Dr. Campbell testified that Chaney made the alleged bite mark to a reasonable degree of dental certainty.

Chaney presented nine alibi witnesses. Despite testimony that generally confirmed Chaney’s whereabouts during the entire day of the crime, he was convicted and sentenced to life.

At the request of Chaney’s legal team, which includes Julie Lesser, exoneration attorney of the Dallas Public Defender’s Office, the Innocence Project and the Southern Methodist University Innocence Clinic, District Attorney Hawk readily agreed to review the case. Her office spent hundreds of hours in its reinvestigation.  In the course of that investigation, the office turned over numerous pieces of previously undisclosed exculpatory evidence, including an earlier finding that there was no blood on Chaney’s shoes as well as numerous contradictory statements made by the informant. DNA testing of all available crime scene evidence, which included fingernail scrapings and hairs found in Sally Sweek’s hand, also excluded Chaney.

“This is yet another in a growing list of cases proving that bite mark evidence has no place in our court rooms,” said Chris Fabricant, Director of the Innocence Project Strategic Litigation Unit.  “There is not a shred of credible scientific research validating the practice, yet for decades courts have allowed these so-called experts to provide incredibly powerful testimony that is nothing more than subjective speculation masquerading as science.  We are grateful to District Attorney Hawk for acknowledging the injustice of Mr. Chaney’s conviction and hope that other district attorneys around the nation will follow her lead by not relying on this discredited evidence and reinvestigating cases where it was used.”  Since 2000, at least 25 people (including Crystal Dawn Weimer just last week in Pennsylvania) have had their convictions reversed or indictments dismissed based on discredited bite mark testimony. If the Court of Criminal Appeals affirms today’s court ruling, Chaney will be the 26



In papers filed Monday, the district attorney’s office agrees that Chaney’s conviction should be reversed based on the recently amended forensic science law (Texas Criminal Procedure Statute 11.073) and based on due process violations that occurred in his trial.  Separate papers filed by Chaney’s lawyers argue that the new evidence establishes his actual innocence.  While the district attorney’s office takes no position on the actual innocence claim at this time, it is continuing to reinvestigate the case.

“Mr. Chaney has maintained his innocence for 28 years,” said Julie Lesser, Exoneration Attorney for the Dallas County Public Defender’s Office.  “We’re confident that when the reinvestigation is complete, the district attorney’s office will be in a position to formally agree that he is innocent of this crime.”

Chaney was surrounded by family and many Dallas area exonerees when he was released from court this afternoon.  The case now goes to the Texas Court of Criminal Appeals to review the agreed findings.


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