A DNA analyst — who was fired and who faced a criminal investigation after “anomalies” were discovered in her work — will not be charged with a crime, the Weld County District Attorney’s Office announced on Thursday.

Chiara Wuensch was fired on Feb. 28 from her position at the Northern Colorado Regional Forensic Lab after more than 10 years working there after an internal investigation identified “anomalies” in her case work. The lab is overseen by the Weld County Sheriffs office.

The district attorney’s office has determined there is not probable cause that Wuensch committed a crime.

A review of Wuensch’s work by the district attorney’s office revealed only five anomalies, the office said. These fell into three categories as identified by the office: Alleged deletion of data indicating a small amount of male DNA, alleged addition of the word “undetermined” to a cell in a spreadsheet, and alleged alteration of values related to potential contamination to a smaller number.

The evidence against Wuensch did not find criminal intent in the data anomalies, the office said in the news release.

The news release quoted Wuensch as saying there was no reason for her to intentionally change the data because she still performed DNA amplification required by standard operating procedures. The district attorney’s said this was confirmed by the Colorado Bureau of Investigations, the lead agency investigating Wuensch’s work.

The bureau also said the anomalies in Wuensch’s work did not affect any DNA identification or elimination in criminal cases.

In a May 23 interview, the DA’s office said Wuensch denied altering or deleting the data on purpose and said the discrepancies could be the result of mistakes in using Excel.

“After a comprehensive review of all the evidence and circumstances, it is clear that the anomalies found in Ms. Wuensch’s work do not meet the legal threshold for criminal charges,” Weld County District Attorney Michael Rourke said in the news release. “The evidence does not support a finding of criminal intent, and therefore, it would be inappropriate to pursue charges in this matter.”

It’s unclear if these findings would affect Wuensch’s termination.

The issues with Wuensch’s casework surfaced because of a separate Colorado Bureau of Investigation probe into its own employees, the Weld County Sheriff’s Office said.

In March, the agency announced a criminal investigation after it said it discovered that its scientist Yvonne “Missy” Woods intentionally cut corners and didn’t follow standard DNA testing protocols, raising questions about hundreds of criminal cases in which she processed evidence. The bureau said Woods was placed on leave after it became aware of irregularities in her work in September 2023, and she resigned before its internal review was completed.

State crime lab employees for years repeatedly tried to warn their superiors at CBI that Woods had become a rogue employee who was cutting corners. But officials failed to respond forcefully until last year, when an intern at the lab found new anomalies, an internal affairs investigation found.

As the regional liaison for Rourke’s office from the Colorado Bureau of Investigation, Woods performed DNA work on many is his cases including a 45-year-old murder case out of Weld County.

In that case, James Dye, 66, faces charges in connection to the rape and murder of Evelyn “Kay” Day, an Aim’s Community College teacher whose body was found five days after Thanksgiving 1979 sexually assaulted and strangled with the belt from her own jacket.

He was not arrested until 2021 after his DNA matched the profile found from spermatozoa found on Day’s body, her coat, pantyhose, underwear, pants and the belt.

The case was dormant until 2011 when technology had advanced enough to identify DNA from Day’s husband, Chuck, on the belt which strangled her. Though the sperm found on Day’s body did not match that of Chuck Day, he was considered a suspect in his wife’s murder but was never arrested, according to a January 2024 Supreme Court filing.

It wasn’t until 2020 that the DNA found on Day’s clothing and body was resubmitted to the Combined DNA Index System, or CODIS, and matched the DNA profile to Dye, a ex-convict living in Wichita.

During a February 2022 preliminary hearing, Dye’s attorneys argued that Chuck Day was an alternate suspect, as the couple was reported to have been having marital struggles.

Still, during the evidentiary hearing, Woods testified that Day’s finger clippings samples showed it was 17 trillion times more likely to be her and Dye’s DNA rather than that of Day and an unidentified person.

Rourke said that he was worried that uncertainty which looms around Wood’s results in the Day murder will affect the work of other forensic scientists and thus make more work for prosecutors as they scramble to retest evidence.

Dye’s next hearing is July 1. There’s no word as to when a trial may happen.

Marissa Solomon of 9NEWS contributed to this story. For more on this story, and others, please visit The Denver Gazette news partners 9NEWS.com.