Problem with DNA robot led to Denver police DNA mix-up

A malfunction in a DNA processing machine led to the scrambling of samples from 11 Denver police burglary cases, officials acknowledged Friday. It took more than two years for the department to discover the errors.

As a result of the mix-up, prosecutors are dismissing burglary cases against four people, three of whom had already pleaded guilty.

All four people had confessed to at least one burglary, but the DNA error meant they were charged with the wrong ones, Denver district attorney spokeswoman Lynn Kimbrough said.

The problem caused evidence from one case to be tied to another. Authorities have since sorted out the samples, but prosecutors won't refile charges against the four people because the statute of limitations has expired. Two of the dismissed cases were against juveniles.

They will file charges in a fifth burglary case, against an adult who is already jailed on unrelated crimes in Adams County, Kimbrough said.

The mistake happened after an $80,000 DNA processing machine "froze" while running a tray of 19 DNA samples on June 13, 2011. An analyst in the city's crime lab then called the manufacturer, which supplied directions for putting the samples back onto the machine in the right sequence. Either the directions were incorrect or the analyst misinterpreted them, and the samples were replaced in the wrong order, said Lt. Matt Murray, the department's chief of staff.

The crime lab didn't suspect the possibility of an error until after the machine froze for a second time on Nov. 22, 2013, and an analyst again requested directions from the manufacturer. The analyst became concerned because the directions seemed different the second time.

Further review over the next month uncovered the earlier mix-up, Murray said.

"The samples were returned to the tray out of sequence," Murray said at a news conference to announce the error. "None of the DNA was compromised; it was merely associated with the wrong case when we were done."

Lab officials notified the police department of the problem late Thursday, he said. District Attorney Mitch Morrissey was notified Friday afternoon.

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Problem with DNA robot led to Denver police DNA mix-up