Barry F. Kowalski, a Justice Department lawyer who prosecuted high-profile civil rights cases, most notably winning the convictions of two white Los Angeles police officers in 1993 for the beating of Rodney G. King — an episode that touched off one of the nation’s worst urban riots — died on Sunday at his home in Arlington, Va. He was 74.
His wife, Katie Zimmerman Kowalski, said the cause was complications of two strokes.
Mr. Kowalski was the assistant chief of the Justice Department’s criminal section in its civil rights division in 1991 when Mr. King’s car was stopped on a June night by four white police officers, who pulled him over for speeding.
A man in an apartment overlooking the scene captured images of the officers beating Mr. King with their batons, kicking him and shocking him with stun guns while he was on the ground. He sold the video to a Los Angeles television station for $500, and it was soon seen throughout the nation.
An all-white jury in state court found the officers not guilty of using excessive force. The trial was held in Simi Valley, a largely white suburb, out of concern that the officers might not get a fair hearing by a Los Angeles jury. The officers testified that their use of force was justified, and their lawyers maintained that the video did not prove otherwise. Mr. King, who had been on parole from a robbery conviction when he was arrested, did not testify.
Hours after the verdicts were announced, rioting broke out in Los Angeles, resulting in more than 50 deaths and an estimated $1 billion in damages, even though Mr. King had famously pleaded at a news conference, “Can we all get along?”
Mr. Kowalski was sent to Los Angeles by the Justice Department soon after the verdicts came in and worked with fellow Justice Department lawyers and other law enforcement officers in an extensive investigation. It led to an indictment of the four officers on federal charges that they had deprived Mr. King of his constitutional rights by beating him with criminal intent, essentially showing malice toward him.
Mr. Kowalski was “a very nice fellow with a great sense of humor,” Richard Cohen, legal director of the Southern Poverty Law Center, who had worked with him in civil rights cases, told The New York Times in March 1993, while Mr. Kowalski was preparing for the federal trial. “At the same time he’s a very tenacious prosecutor. He’s been called the Justice Department’s pit bull.”
Mr. Kowalski joined with Steven D. Clymer, an assistant United States attorney, in arguing the federal case in Los Angeles before a jury that included two members who were black and one who was Latino. Although the video was shown once again, they concentrated on seeking to convince the jury that the officers had lied in their accounts of what happened. This time Mr. King did testify, providing a human element missing in the first trial.
“Let’s call it like it is,” Mr. Kowalski told the jury in his closing argument, describing the defendants as “bullies with badges.”
The two officers who were convicted were sentenced to 30 months in prison. In the years that followed, Mr. King was in and out of jail and struggled with drug and alcohol abuse. He died in 2012 at 47.
Mr. Kowalski served in the Justice Department from 1981 to 2014.
Soon after he joined, he investigated the death of a 19-year-old black man, Michael Donald, who was abducted in Mobile, Ala. Mr. Donald was beaten, his throat was slashed and he was found hanging from a tree.
The investigation led to the arrests of two Klansmen. One, James Knowles, confessed in federal court to violating Mr. Donald’s rights and was sentenced to life in prison. He implicated the other Klansman, Henry Hays, who was found guilty of murder in state court and died in the Alabama electric chair. The killing financially destroyed the United Klans of America in 1987 when a jury found it liable in a wrongful-death case brought by Mr. Donald’s mother and ordered it to pay $7 million, which it did not have.
Mr. Kowalski won convictions of neo-Nazis in the June 1984 murder of Alan Berg, a Jewish radio talk-show host, who was gunned down outside his home in Denver.
He led a Justice Department inquiry into allegations that James Earl Ray’s assassination of the Rev. Dr. Martin Luther King Jr. in Memphis in 1968 was part of a conspiracy. The investigation ended in 2000 without finding evidence to substantiate any of the claims.
Barry Frank Kowalski was born in Hartford on Aug. 26, 1944, to Frank Kowalski, a career Army officer, and Helen (Bober) Kowalski, a homemaker and amateur artist.
His family settled in the Washington area after his father was elected to Congress in 1958 as an at-large Democratic representative from Connecticut. He served two terms in the House.
Mr. Kowalski graduated from Brown University in 1966 with a bachelor’s degree in political science. He was commissioned as a Marine lieutenant and commanded an infantry platoon in combat in the Vietnam War.
He received a law degree from Catholic University of Washington in 1973 and taught at the Antioch School of Law there before joining the Justice Department.
Beyond the courtroom, Mr. Kowalski had a calling as an amateur cowboy. He rode horses that his family kept on a Virginia farm, took part in rodeos and wrote cowboy poems and songs.
In addition to his wife, a specialist in international public health issues, he is survived by their daughters, Bailey and Hallie Kowalski; another daughter, Kelly Kowalski, from his marriage to Lynn Gardner Heffron, which ended in divorce; a sister, Carol Reidy; and two granddaughters.
When the verdict in the federal Rodney King case came in, Mr. Kowalski reflected on his mission.
“I think a year ago the conscience of the community, the conscience of the nation cried out for justice,” he said, “and this verdict provides justice.”
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