Rudolph W. Giuliani likens himself to a boxer who never takes a punch without swinging back. As mayor, he made the vengeful roundhouse an instrument of government, clipping anyone who crossed him.

In August 1997, James Schillaci, a rough-hewn chauffeur from the Bronx, dialed Mayor Giuliani's radio program on WABC-AM to complain about a red-light sting run by the police near the Bronx Zoo. When the call yielded no results, Mr. Schillaci turned to The Daily News, which then ran a photo of the red light and this front page headline: "GOTCHA!"

That morning, police officers appeared on Mr. Schillaci's
doorstep. What are you going to do, Mr. Schillaci asked, arrest me? He was joking, but the officers were not.

They slapped on handcuffs and took him to court on a 13-year-old traffic warrant. A judge threw out the charge. A police spokeswoman later read Mr. Schillaci's decades-old criminal rap sheet to a reporter for The Daily News, a move of questionable legality because the state restricts how such information is released. She said, falsely, that he had been convicted of sodomy.

Then Mr. Giuliani took up the cudgel.

"Mr. Schillaci was posing as an altruistic whistle-blower," the mayor told reporters at the time. "Maybe he's dishonest enough to lie about police officers."

Mr. Schillaci suffered an emotional breakdown, was briefly hospitalized and later received a $290,000 legal settlement from the city. "It really damaged me," said Mr. Schillaci, now 60, massaging his face with thick hands. "I thought I was doing something good for once, my civic duty and all. Then he steps on me."