WILLIAMS BAY — It was one of the darkest moments in Wisconsin history, and it resulted in one of the state’s most infamous criminal cases of the 1970s.

And John Olson was right in the middle of things.

Olson, an attorney from Walworth County, was a federal prosecutor who got the first conviction in the 1970 war-protest bombing of Sterling Hall at the University of Wisconsin in Madison.

Putting bomber Karleton Armstrong behind bars remained Olson’s proudest professional achievement in a long and distinguished career.

“Those were tumultuous times,” said his daughter, Sheree Olson Rogers. “And he was a law-and-order kind of guy.”

Olson, who continued to practice law privately for another 40 years in Lake Geneva, died May 4 following a battle with Parkinson’s disease. He was 82 years old.

Former law partner Dan Draper describes Olson as a gifted litigator who won long-shot cases that often seemed like lost causes before he took them on.

“He was an incredibly good lawyer,” Draper said. “He had a very big presence in the courtroom.”

Born in Whitewater, John Olmstead Olson graduated from Milton High School and enlisted in the U.S. Air Force just after the Korean War. He got his law degree from UW-Madison in 1963 and served as district attorney in Taylor County, north of Madison.

After an unsuccessful run for Wisconsin attorney general in 1966, he was appointed by President Nixon in 1969 as U.S. attorney in the western district of Wisconsin.

One year later, UW student protests against the Vietnam War turned deadly when protesters detonated a bomb outside Sterling Hall, a campus building where researchers did work for the military. The blast killed a faculty member and injured three other people.

The first bomber captured was Karleton Armstrong, whom Olson prosecuted, winning a conviction and a lengthy prison term. Armstrong ended up spending about seven years behind bars.

Rogers, a high school freshman at the time, remembers her father spending long nights and weekends at the office, working to ensure that justice was served in the bombing case.

“That was a big time in our lives,” she said. “He was certainly passionate about investigating what happened and who was responsible.”

Two other suspects were later charged, and a fourth remains a fugitive to this day.

Olson stepped down from his U.S. attorney’s appointment in 1974, and he and his family returned to Walworth County. He and his wife, Marjorie, had four children. The marriage ended in divorce, and he remarried.

Living in Whitewater and later in Williams Bay, Olson was an active member of the Whitewater Lions Club.

Fellow club member Bernie Tangney says Olson was a shrewd attorney who enjoyed relaxing with his Lions Club friends and being “just one of the guys.”

“He was a man who became successful, but hadn’t forgotten his roots,” Tangney said.

In 2014, the Walworth County Bar Association recognized him with a lifetime achievement award.

His daughter says Olson talked later in the life about feeling proud of the Sterling Hall case. He thought about retiring many times, she said, but he continued practicing law as long as he could.

“In the end,” she said, “he wanted to be a lawyer.”