He also made sure he was noticed on the streets of Paterson, where he had returned to live. He dressed in custom-tailored suits and drove a black Cadillac Eldorado with “Rubin Hurricane Carter” engraved in silver letters on each side of the headlights. In 1963 he married Mae Thelma Basket.

Mr. Carter’s biggest victory came in Pittsburgh in December 1963, when he knocked out Emile Griffith, the welterweight champion, who was trying to move into the middleweight division for a crack at its world title. A year later, at the peak of his career, Mr. Carter battled the reigning middleweight champion, Joey Giardello, for the title in Philadelphia, Mr. Giardello’s hometown. He lost a close decision.

Mr. Carter received unfavorable attention when an article in The Saturday Evening Post in 1964 suggested that he was a black militant who believed that blacks should shoot at the police if they felt they were being victimized. He denied he had expressed that view. It was around this time that the police began harassing him, he said. One night, when his Cadillac broke down in Hackensack, he was jailed for several hours without being charged with a crime.

Before bouts, the police compelled him to be fingerprinted and photographed for their files on the ground that he was a convicted felon. He discovered that the Federal Bureau of Investigation had opened a file on him and was tracking his movements.

On the night of June 16 and the early morning of June 17, 1966, while his wife and their 2-year-old daughter, Theodora, were at home, Mr. Carter visited several bars in Paterson, winding up at one called the Night Spot.

A half-mile away, about 2:30 a.m., two black men entered the Lafayette Grill and killed two white men and a white woman in a barrage of shotgun and pistol blasts. The police immediately suspected that the shootings were in retaliation for the shotgun murder that night in Paterson of a black tavern owner by the former owner, who was white.

Mr. Carter had encountered John Artis, a casual acquaintance, that night and was giving him a lift home when they were stopped by the police. They said Mr. Carter’s leased white Dodge sedan resembled the murderers’ getaway car. Except for being black, neither Mr. Carter nor Mr. Artis matched the original descriptions of the killers. They were released after both passed lie detector tests and a patron who had been wounded in the Lafayette Grill failed to identify them. But they remained under suspicion.