Harold “Hal” Fabriz, a veteran FBI agent who worked the front lines of the civil rights movement in the 1960s, helped prevent violence in Mississippi by calming angry bigots and keeping his cool after being spit in the face by hostile Ku Klux Klan members.

Fabriz, who also played a small role in investigating the assassinations of President John F. Kennedy and civil rights leader Martin Luther King Jr., died Nov. 25 at age 85. He was a longtime resident of Falcon Heights.

“Hal was a great arbitrator,” said Bob Agnew, a former FBI agent who worked with Fabriz for three years in Mississippi. “I think he contributed a great deal to keeping the peace to the greatest extent possible in Mississippi during some very turbulent times.

Born in Minneapolis, Fabriz — who stood 6 feet, 6 inches tall and wore a size 15 shoe — attracted the nicknames “Moose” and “Big Foot” as a student at Roosevelt High School. He heard about police work as a child from his father, Wilzel “Duke” Fabriz, who spent 20 years on the force in Minneapolis and later served as chief deputy sheriff of Hennepin County.

After earning a degree in criminal science from Michigan State University, Fabriz joined the FBI in 1962. His first posting was in San Antonio, Texas, arriving a few months before the Kennedy assassination. As part of the investigation, he interviewed friends of Marina Oswald, the widow of Kennedy’s killer, Lee Harvey Oswald.

His next posting was in Mississippi, where Fabriz handled civil rights investigations, bank robberies and other high-profile cases from 1964 to 1973, a period of extraordinary civil unrest.

“We’d be working with the police one day and investigating them the next,” Agnew said.

Fabriz often shadowed KKK members and other agitators. Once, after hearing about a white farmer firing a gun at activists who were trying to register black voters on his property, Fabriz convinced the man to go to court for a restraining order if the invaders returned instead of using his gun. Agnew said Fabriz always found creative ways to defuse tense situations.

“Dad was a lawman — he wasn’t a crusader,” said daughter Sharon Fabriz. “He carried out his duties with as much integrity as possible, but he never made it into a personal cause.”

Sharon said her father sheltered the family from his work as much as possible.

“We were nervous about him getting home safely every day, but he didn’t lay the worries of the world on his family,” she said.

Sharon said her father didn’t open up about his work until the movie “Mississippi Burning” came out in 1988. The film, which chronicled the federal response to the death of three civil rights workers in Philadelphia, Miss., prompted questions from his family about his role in the case. Fabriz was one of hundreds of FBI agents involved in an investigation that led to the convictions of seven men, including the deputy sheriff who originally arrested the workers.

“He always minimized his role,” Sharon said. “He was a humble man.”

Fabriz finished his FBI career in Minnesota, retiring in 1987. He spent the last 16 years of his professional life doing drug testing for the National Football League, primarily working with the Vikings.

“Our dad collected Warren Moon’s pee,” said Sharon, referring to the former Vikings quarterback.

Survivors include his wife of 30 years, Patricia Fabriz; daughters Sharon Fabriz and Dawn Phillips of Houston; and stepdaughter Thekla Fagerlie Madsen of River Falls, Wis. Services have been held.