SOUTH ST. PAUL, Minn. (WCCO) — It was a south Minneapolis apartment building where a routine search warrant targeted a wanted drug dealer.

On Sept. 15, 2017, Minneapolis SWAT officers found the evidence prosecutors needed to send Timothy Holmes to prison.

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“I’ve been a prosecutor in Hennepin County over 30 years, I’ve never seen anything like this,” Chief Deputy Hennepin County Attorney David Brown said on Friday.

The department held a news conference to reveal alleged police misconduct by Eden Prairie Detective Travis Serafin. Brown said Serafin’s handling of the search warrant put other past cases into question and will likely result in dozens of dismissed cases.

“He’s got an unblemished record over 19 years,” Paul Rogosheske, Serafin’s attorney, said.

Rogosheske says his client is a highly honored and respected drug detective who made a simple clerical mistake on the warrant in question. He vehemently denies there was any intentional misconduct on Serafin’s part.

“What happened is he was rushed and didn’t change that part of the warrant. But probable cause has (vehicle reference) it in it. He would have changed it if he had put the template in it,” Rogosheske said.

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The initial search warrant signed by a Hennepin County Judge did not list vehicles at the south Minneapolis property. Serafin claims he used the wrong template when applying for the warrant.

But days later when the executed warrant was returned and filed with the court, its wording on the cover page had been altered to include any vehicles at the property. Some small amounts of heroin were found in a vehicle, but the evidence was not essential in proving the state’s case against Holmes.

Rogosheske says Serafin’s intent for adding the corrected template was to make it consistent with the warrant’s probable cause referencing the suspect’s vehicles.

“Things get lost, so he reproduced the original first page thinking, this is what we always do. It was a mistake!” Rogosheske said.

But how costly of a mistake is still being calculated. The Hennepin County Attorney’s Office is reviewing past cases where Serafin played a major role. They have started notifying defendant’s counsel for the possible filing of motions for dismissal.

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Meantime, McLeod County has been selected as an outside agency to consider if Serafin’s actions rise to criminal wrongdoing. Any decision is likely weeks away.