Gerald Shur, a lawyer who created the federal witness protection program, died August 25 at his home in Warminster, Pa. He was 86.

In 1961, Mr. Shur became an early recruit in the crusade by Robert F. Kennedy, then the attorney general, to break the grip of organized crime in the United States. Joining the Justice Department that year as a lawyer assigned to New York, he was tasked with investigating the mob.

“In the course of that,” he told The Associated Press in 2007, “I began to hear people say, ‘I can’t testify; I’ll be murdered before or after I testify.’”

During Mr. Shur’s 34 years at the Justice Department, 6,416 witnesses and thousands of their dependents, including wives, children and mistresses were given new identities and relocated, according to Pete Earley, who with Mr. Shur wrote the 2002 book WITSEC: Inside the Federal Witness Protection Program.