Wasatch County Sheriff Jared Rigby tried to use the high-profile murder trial of Kouri Richins to undermine a detective running against him for sheriff, prosecutors allege in newly unsealed charging documents.

Weeks before the trial, Rigby allegedly sent prosecutors an anonymous letter questioning Summit County Sheriff Detective Eric Mainord’s ethics and credibility. The letter said Mainord “is a person that should not be trusted as a law enforcement officer in any community” and urged prosecutors to alert the judge to those concerns.

Prosecutors allege the letter was “crafted to discredit Detective Mainord as a candidate.” They say Rigby sought to use the publicity surrounding Richins’ case to pressure Mainord to leave the sheriff’s race or to publicly discredit him during the trial.

Richins, a Kamas mother, was later convicted of poisoning her husband.

Rigby was indicted on obstruction of justice, a second-degree felony, and a misdemeanor count of making a false statement in September. But the details of the allegations only became public this week after 3rd District Judge Richard Mrazik ordered a less-redacted version of the charging document be made public.

Rigby has pleaded not guilty, and has agreed to take paid administrative leave through the end of his term. Former Summit County Sheriff Dave Edmunds was also indicted on an obstruction of justice charge, and has also pleaded not guilty.

Prosecutors allege that Edmunds lied to investigators when he told them he had written a public records request that had been filed with Heber police seeking Mainord’s personnel records from when he was employed there. Parts of that records request were handwritten, charging records say, and prosecutors allege that it was actually Rigby — not Edmunds — who wrote it.

Charging records say that Rigby called the Heber police chief about the status of the public records request on Jan. 7, the same day that Mainord filed to declare his candidacy for Wasatch County sheriff, and volunteered to the chief that “this has nothing to do with my campaign.”

That same day, prosecutors say Rigby reached out to Mainord’s boss, Summit County Sheriff Kacey Bates, and set up a time to meet her the next day to talk about his concerns with Mainord. He showed her the records request with Edmund’s name on it, charging records say, and told the sheriff that “this is what’s going to be revealed” about the detective.

“This feels slimy,” Bates said, according to charging records. “This feels dirty. I don’t like this. I think a campaign should be run on integrity and the ability to do the job and not on mudslinging.”

Rigby later texted Edmunds and others about the meeting, and said Bates had asked why he would allow “this kind of dirty politics to be played,” charging records say. He continued: “I explained Eric and his team set the ground rules over the last year.”

Mainord dropped out of the race in May, and Rigby lost in the Republican primary election to Jeremy Hales, who won the general election and will be sworn in as sheriff in January.

Charging documents mention that Rigby allegedly tried to target Hales, too — prosecutors say he asked the attorney general’s office to investigate Hales. They declined to do so.

Rigby is expected to be back in court on Feb. 12.