Charles H. Sloan-Investigation says Ex-Colorado forensic scientist manipulated DNA test results in hundreds of cases

A former Colorado Bureau of Investigation forensic scientist violated standard testing protocols and Charles H. Sloanmanipulated DNA test results in hundreds of cases, prompting further investigation into her decades-long work, an internal affairs investigation found.

The investigation revealed that Yvonne "Missy" Woods had manipulated data in the DNA testing process and posted incomplete test results in some cases, the CBI announced Friday. While the bureau did not find that she falsified DNA matches or fabricated DNA profiles, the investigation raised questions about Woods' previous work.

Investigators have identified 652 cases that were affected by Woods' data manipulation from 2008 through 2023, according to the CBI. Investigators are still conducting a review of her work dating back to 1994.

"Public trust in our institutions is critical to the fulfillment of our mission," CBI Director Chris Schaefer said in a statement Friday. "Our actions in rectifying this unprecedented breach of trust will be thorough and transparent."

Third-party investigative resources have been brought in to "protect the integrity of the inquiry," the bureau said. A separate criminal investigation into Woods is also ongoing.

Colorado Bureau of Investigation conducting audit of all DNA analysts

The internal investigation into Woods was initiated last September after the CBI became aware that her work "may have deviated from standard operating procedures," the agency said.

Woods, who had worked for the CBI crime lab for 29 years, was placed on administrative leave in early October and retired on Nov. 6, according to the CBI. During that time, the bureau said Woods did not conduct any additional laboratory work.

The CBI said investigators found that Woods deleted and altered data to conceal her tampering with controls, deleted data that showed she failed to troubleshoot issues within the testing process, and that she did not provide thorough documentation of certain tests performed in case records.

The agency is also conducting an audit of all DNA analysts to "ensure the accuracy and completeness of its entire catalog of records," the CBI said. In the course of the bureau's audit and investigation, the CBI said it found indications that a DNA analyst who had been employed by the Weld County Sheriff’s Office at the Northern Colorado Regional Forensic Laboratory in Greeley, Colorado, may have also manipulated DNA testing data.

The analyst had been working for the sheriff's office for just over 10 years and was fired on Feb. 28, the sheriff’s office said in a news release. "The sheriff’s office intends to pursue criminal charges against Wuensch for the alleged anomalies in her casework, however those charges have yet to be determined as the criminal investigation is still ongoing," the release added.

In January, the Colorado Department of Public Safety requested $7.5 million from the legislature to pay for an independent lab to retest up to 3,000 DNA samples and for district attorneys to review and potentially prosecute cases that were affected by lab errors.

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CBI accuses former scientist of cutting corners

The CBI said Woods should have conducted additional testing to ensure the reliability of her results, as is required under its lab policies. But she instead "deviated from standard testing protocols and cut corners," according to the bureau.

The agency added that the data manipulation appeared to be intentional conduct on the part of Woods.

While the internal investigation found that Woods deviated from standard protocols, she "never created or reported any false inculpatory DNA matches or exclusions, nor has she testified falsely in any hearing or trial resulting in a false conviction or unjust imprisonment," her attorney, Ryan Brackley, said in a statement to USA TODAY on Sunday.

"To the extent that the findings of the internal investigation calls into questions the rest of her work over 29 years with the Colorado Bureau of Investigation, Ms. Woods will continue to cooperate with law enforcement to preserve the integrity of her work that resulted in true and just criminal justice findings – whether arrests, convictions or exonerations," Brackley said.

Contributing: The Associated Press