Hennepin County Sheriff’s Office stops all DNA analysis after crime lab contamination

The Hennepin County Sheriff’s Office has paused all DNA casework while it investigates contamination in its crime lab, according to documents obtained by the Star Tribune. The investigation is ongoing and has identified approximately 75 cases that have been impacted.

Laboratory Director Capt. Steve Labatt sent an email on Sept. 26 alerting the Hennepin County Attorney’s Office that DNA personnel at the lab had discovered “sporadic DNA contamination” in their casework and it likely originated “from an external product we use in the DNA testing process.”

An internal memo from Hennepin County Managing Attorney Dan Allard on Monday said the latest update from the crime lab shows the contamination appears at random in casework but matches a DNA profile from a discharged shell casing from 2022 from an unknown male. The lab recognized the contamination when that DNA profile showed up as a “reagent blank” or negative control that is meant to highlight contamination.

“There will be months, or even a year or more, where it didn’t show up and then would appear a number of times in a short period of time,” Allard wrote while noting that the crime lab has examined all of its data from 2016 through 2024 to identify the contamination in any casework.

He added that several other accredited forensic labs across the country have found this profile in their lab. The 75 cases that the Hennepin County Sheriff’s Office has identified are “impacted in part by the inability to rule out the presence of the contaminating profile rather than the clear presence of the contaminating profile.”

The next step in the process could include retesting the DNA. The Hennepin County Attorney’s Office does not know what specific cases have been impacted and therefore doesn’t know how many are active investigations.

When Labatt first emailed the Sheriff’s Office about the contamination on Sept. 26, he noted fewer than 10 cases were impacted. But the lab needed to work back through its casework to see if there was other contamination and that’s why it had to pause all DNA casework.

One day later, on Sept. 27, Hennepin County Managing Attorney Michael Radmer sent an internal email to county prosecutors that the crime lab would be preparing a list of all impacted cases and that the Hennepin County Attorney’s Office had asked them to “identify upcoming cases set for trial with DNA evidence analyzed by the HCSO Crime Lab.”

Allard updated the office in an internal memo on Sept. 30 after speaking with Allison Dolenc, the DNA section supervisor at the sheriff’s crime lab.

That memo included the following information:

The crime lab noticed the contamination two weeks before the initial email from Labatt. They immediately stopped all work on those cases, but hadn’t released any findings related to contamination on those cases. The crime lab then started looking for other cases that may have been impacted by contamination — the first cases to be found with contamination were in 2022 and the lab was looking back to 2016. At the time of that email, the HCSO was looking at cases in 2018. Dolenc told Allard the source of the contamination “likely came from plasticware” that was used in DNA testing.

There was an update two days later that the crime lab had identified 12 impacted cases, two of which were active.

There are three other crime labs in the state that can process DNA evidence and “forensic serology” which is analysis of bodily fluids like blood, semen, saliva and urine: The Minnesota Bureau of Criminal Apprehension labs in St. Paul and Bemidji and the Tri County Regional Forensic Laboratory in Andover.

The HCSO crime lab works with 35 law enforcement agencies in Hennepin County along with the State Patrol and federal law enforcement agencies. The Minneapolis Police Department works with the BCA crime lab; their contract this year was for $1.32 million.

Last week, Assistant Hennepin County Public Defender Laura Johnson sent an internal email addressing the contamination in the crime lab.

“They estimate it only impacts a few cases,” Johnson wrote, “but quite honestly, I think it would make for a great cross examination even if your case isn’t impacted.”

Hennepin County Chief Public Defender Mike Berger said in a written statement that, “The transparency afforded by the Sheriff’s Office is an important first step, and we are prepared to litigate all issues in all effected cases as they arise.”

Calls seeking comment with the Hennepin County Sheriff’s Office and the Hennepin County Attorney’s Office were not immediately returned.

This is a breaking news story. Come back to Startribune.com for updates.