In 1976, Frank Fitzsimmons, president of the Teamsters, struck a defiant note in a speech at the union’s convention in Las Vegas. “To those who say it is time to reform this organization, and it’s time officers stopped selling out the members,” he said, “I say to them, ‘Go to hell.’ ”

The next day, Pete Camarata, a rank-and-file Teamster dedicated to reform, rose to say he opposed Mr. Fitzsimmons’s re-election as well as a pay raise for him. He said Mr. Fitzsimmons and his lieutenants had stifled democracy in the union and ignored workers’ concerns. He called for a rule that would automatically expel any Teamster officer who accepted a bribe from an employer.

Boos and catcalls drowned out his remarks.

Afterward, Mr. Camarata — who died last Sunday in Chicago at 67 — attended a cocktail party in the hotel ballroom, but felt unwelcome and excused himself. Several beefy sergeants-at-arms offered to escort him outside. (Mr. Camarata himself was a hefty man, at one point weighing 400 pounds.) Suddenly, one of them punched him. Others kicked him in the head with their pointed cowboy boots. His face was left purple and swollen, his right eye closed.

The police were sympathetic, until they conferred with Teamster officials. According to Lester Velie’s 1977 book about the Teamsters leader Jimmy Hoffa, “Desperate Bargain: Why Jimmy Hoffa Had to Die,” one officer then said, “Get out of town, buddy, and get out fast.”