Colorado DNA scandal threatens to overturn hundreds of criminal cases

Hundreds of criminal convictions may now be re-examined after investigators in Colorado found that one of their DNA analysts manipulated testing samples.

Yvonne "Missy" Woods is accused of manipulating data during her 29-year career for the Colorado Bureau of Investigation's (CBI) crime lab.

On Friday, the CBI said they had found 652 cases affected by her recent work. Some 3,000 samples require re-testing.

No charges have been filed against Ms Woods, who has retired from the CBI.

Officials are now examining all of her work, dating back to 1994. The CBI has set aside $7.5m (£5.8m) to conduct new tests, re-try cases and potentially reimburse inmates for wrongful convictions.

The statement issued by the CBI on Friday said that Ms Woods' tampering appeared to be "intentional conduct", adding that "this discovery puts all of her work in question".

Officials say she deleted, altered and omitted data in official criminal justice records. So far, they have identified problems in 652 cases she worked on between 2008 to 2023. Her work from 1994 to 2008 is still being reviewed.

"The review did not find that Woods falsified DNA matches or otherwise fabricated DNA profiles. She instead deviated from standard testing protocols and cut corners, calling into question the reliability of the testing she conducted," the statement says.

Her lawyer on Friday told the Denver Post that she is co-operating with the investigation and stands by her work, which he called the result of "true and just criminal justice findings".

"While the allegations resulting from the internal investigation point to Ms Woods deviating from standard protocols and cutting corners in her work, she has long maintained that she's never created or falsely reported any inculpatory DNA matches or exclusions, nor has she testified falsely in any hearing or trial resulting in a false conviction or unjust imprisonment," he said in a statement.

A criminal probe of Ms Woods activities is still underway.

"Public trust in our institutions is critical to the fulfilment of our mission," said CBI Director Chris Schaefer.

"Our actions in rectifying this unprecedented breach of trust will be thorough and transparent."

The CBI is now performing an audit of all its DNA analysts, leading to the discovery of another scientist alleged to have manipulated data.

Chiara Wuensch was fired from the Weld County Sherriff's Office last week after the CBI discovered anomalies in her work. She is also now under a separate investigation.