Convicted of murder, he served 11 years in prison before being paroled in 1982, two years after the prosecutor determined that he had not been at the crime scene. His accomplices, including his brother Jacques, were convicted of lesser offenses and served shorter terms.

“I regret nothing: 1970, the abductions, the prison, the suffering, nothing,” Mr. Rose later said of the killing of Mr. Laporte. “I did what I had to do. Placed before the same set of circumstances today, I would do exactly the same thing. I will not deny what I did and what happened. It was not a youthful indiscretion.”

In 1982, Francis Simard, another accomplice, called the murder “a sincere gesture to show that what we were saying was not just words.”

Mr. Cross, the British official, was released weeks after his abduction when, in exchange, the Canadian government agreed to grant his kidnappers safe passage to Cuba, with the approval of Fidel Castro.

Many Quebecers who favored independence from Canada were contemptuous of Mr. Rose and the F.L.Q. René Lévesque, father of the separatist Parti Québécois, which held seven seats in the provincial legislature in 1970 and gained power in 1976, called the members of the group subhuman. The party, which governs Quebec today, received mainly praise for denying requests that the legislature honor Mr. Rose’s death.

Paul Rose was born on Oct. 16, 1943, in Montreal to a factory worker and a seamstress and grew up in working-class areas of Montreal. He later worked with disabled children and started a youth retreat for hippies in eastern Quebec.

Mr. Rose was said to have taken part in his first protest at 12 as a striking strawberry picker. He was one of 290 demonstrators arrested in an anti-Trudeau riot in Montreal in 1968.