JACKSON, Miss. — Mayor Frank Melton came into office like a Wild West marshal sworn to clean up the town. But somewhere along the line, prosecutors say, the crime-fighting mayor crossed over from lawman to vigilante.

Mr. Melton and two police detectives pleaded not guilty yesterday to charges of malicious mischief and burglary. He was indicted last week and accused of leading a group of teenagers with sledgehammers in smashing up a house that he claimed was a drug den and was also charged with carrying a gun on school property.

Mr. Melton and detectives Marcus Wright and Michael Recio face trial in Hinds County Circuit Court on November 7. If found guilty, Mr. Melton could get up to 50 years in prison.

The indictment was the culmination of a furor that had been building for months around Mr. Melton, the city’s second black mayor in modern times, over his penchant for picking up a gun, putting on police gear, and taking part in sweeps, raids, and roadblocks despite warnings from prosecutors that he was impersonating an officer.

The arrest has led many people in this crime-ridden city to rally to Mr. Melton’s side. Days after his indictment, the mayor promised a throng of supporters outside City Hall that he would stay the course, despite calls for his resignation from some City Council members.

“I’m going through very tough times … but I’ve been through them before,” the former TV executive and director of the state narcotics agency said. “Will I continue to take down houses? Absolutely. I’m going to make sure they’re legally taken down, but we’re going to continue to aggressively take down the crack houses in Jackson, Mississippi.”

Mr. Melton, 57,a native of Texas, made his mark in Jackson in the early 1980s when he became a major shareholder in Civic Communications Inc., a minority-owned broadcast company. He oversaw day-to-day operations at WLBT-TV in Jackson. He established himself as a crime fighter with his tough-talking approach on the “Bottom Line,” an opinion piece on WLBT. He would name suspected criminals on the air.

A longtime friend who worked for Mr. Melton for 17 years, Dan Modisett, said the company was sold in 2000 for $204 million. The millionaire Mr. Melton then began to devote much of his time to inner-city youngsters, trying to keep boys from joining gangs. He volunteered at a YMCA in one of the city’s poor areas.

Mr. Modisett detected a certain ends-justify-the-means mentality in Mr. Melton back then, recounting a conversation he had with Mr. Melton over posting pictures of drug dealers on billboards.

“I said, ‘Frank, don’t put those billboards up. We’re going to get sued.’ He said, ‘I don’t believe you’re going to get in trouble for doing the right thing,'” Mr. Modisett said. Mr. Melton got elected mayor with 88% of the vote and took office 14 months ago with a promise to bring down crime in the city of 184,000, which is 71% black and has a crime rate nearly twice the national average.

“Fundamentally, I don’t think he has any interest in governing the city of Jackson,” a political scientist at Jackson State University, City Councilman Leslie McLemore, said. “Every aspect of city government he has neglected, from housing to infrastructure.”

The mayor told the Associated Press in a July interview that he was driven by “passion and guilt.” Mr. Melton grew up in Houston’s notoriously crime-ridden Fifth Ward.

“We were poor,” Mr. Melton said. “And now I’ve done well, and I feel guilty.”

As mayor, in addition to joining the SWAT team on crime sweeps, he has allowed poor young people to stay in his home and offered protective custody to crime witnesses. In July, with the crime rate still climbing, he declared a state of emergency, basically adopting a stricter curfew for teenagers and homeless people.

The American Civil Liberties Union accused him of trampling on people’s rights and engaging in racial profiling.

On the night of August 26, the mayor and a group of boys nearly destroyed a duplex where a man named Evans Welch lived, according to investigators. A spokesman for the mayor acknowledged no drugs were found. Mr. Welch was arrested on charges of possession of drug paraphernalia.

Mr. Melton’s attorney, Dale Danks, suggested the charges against the mayor were politically motivated on District Attorney Faye Peterson’s part and insisted the smashed-up home was a “drug house.”

“Maybe better judgment could’ve been used, but the charges that have been made against Mayor Melton are an extreme and excessive reaction,” Mr. Danks said.