After nearly 40 years in law enforcement, Dakota County Sheriff Don Gudmundson announced Monday that he won't seek reelection next year.

Gudmundson, 62, is believed to be the only sheriff to have been elected in two Minnesota counties. He also served as sheriff in Fillmore County, where he was raised.

He is known as a mentor who fostered laughter in the halls and breakrooms of the departments where he worked to counter the sorrow that can permeate police work.

"Like many police chiefs, I have been in the middle of the worst sorrow of people's lives," Gudmundson said in an interview. "Whether it was murder or traffic fatalities or suicides or drug overdoses or accidental deaths ... I've been to hundreds of those death scenes."

One might think that over the years, it would have gotten easier. It hasn't.

"It's painful to ring on that doorbell in the middle of the night, to knock on that door, knowing the minute that you do that the lives behind that door will change forever," he said. "I've done that too many times. I'm going to finish my term up, God willing, but it's time for someone else to do those things."

Those who've worked with him say his ability to use wit to break the tension helped him keep his department healthy in his four terms as Dakota County sheriff and, before that, when turning around an ailing Lakeville Police Department as its chief.

"One of the things that many people don't get to see and appreciate is how he would always work humor into so many situations," said Tom Vonhof, the current Lakeville chief.

In 1989, when Gudmundson began in Lakeville, there was internal strife. One night, Gudmundson said, he heard an officer break into laughter. Gudmundson strode out of his office and told the surprised officers that he wanted to hear more of that.

Vonhof is among a dozen or so of Gudmundson's protegés who have gone on to become police chiefs, deputy chiefs and sheriffs under his tutelage. They're a group who affectionately refer to themselves as "the disciples of Don," joked Dakota County Chief Deputy Dave Bellows.

Gudmundson also was among the few officers to enter policing with a college education. He helped lead the field as it evolved from a blue-collar to a white-collar profession where degrees are required, Bellows said.

Gudmundson earned a biology degree from Concordia College in Moorhead. He taught high school biology near Rochester for two years before he first put on a badge in 1971 as a Detroit patrol officer. He later became the youngest homicide detective in Detroit police history.

He moved on to Chicago where he investigated Mafia assassinations. Then in 1978, he returned to Fillmore County as sheriff, and taught criminal justice at Winona State University.

Fillmore County Sheriff Daryl Jensen is one of those who benefited from Gudmundson's mentoring.

"Next to my father, he's probably made a bigger impact on my life than anyone else," Jensen said Monday.

"I was lucky enough in my life to have older, experienced officers who were concerned about me as a person and as an officer," Gudmundson said. "I always felt like it was my obligation to mentor others."

Joy Powell • 952-882-9017 Katie Humphrey • 952-882-9056