J.W. Carney, defense attorney for accused mob boss James "Whitey" Bulger, talks to reporters as he arrives at the U.S. Federal Courthouse for the start of Bulger's trial in Boston, Massachusetts June 12, 2013. Bulger is accused of committing or ordering 19 murders while running Boston's "Winter Hill" crime gang in the 1970s and 80s. (BRIAN SNYDER/REUTERS)

The trial of James “Whitey” Bulger, the Irish mob boss who allegedly helped scratch out 19 lives and ran this city’s underworld aided by corrupt FBI agents, got underway Wednesday morning almost 20 years after he fled the city on the eve of his indictment.

Now 83 and with just a bit of white hair left, Bulger wore a long-sleeve green shirt and jeans and listened without displaying any reaction as prosecutors laid out their 32 charges against him in a packed South Boston federal courtroom near the gangster’s old hangouts.

“It’s a case about organized crime, public corruption and all types of illegal activities,” federal prosecutor Brian Kelly said during opening statements. “He was no ordinary leader. He did the dirty work himself. He was a hands-on killer.”

Kelly told the story of one of Bulger’s alleged murder victims, Arthur “Bucky” Barrett, who prayed for his life before he was led to a cellar stairwell. “Barrett’s going downstairs to lie down for a while,” Bulger told an accomplice. Barrett walked down the stairs, and Bulger shot him the back, Kelly said.

Bulger’s rise as the city’s brutal organized crime leader was aided and abetted by corrupt FBI agents, who brushed off Bulger’s racketeering and violence in exchange for his help as an informant to bring down the local mafia, according to a lengthy ruling by a federal judge and other investigations.

A 2004 report on FBI informants by the House Committee on Oversight and Government Reform found “no doubt” that law-enforcement personnel, including FBI officials, were aware that informants, including Bulger, “were committing murders.”

Bulger’s FBI handler, John Connolly, grew up near Bulger in a hardscrabble South Boston housing complex. They hooked up as adults with a shared interest in bringing down the New England Mafia — Connolly, because of the FBI’s obsession with Italian organized crime, and Bulger, because it was his primary competition.

Connolly tipped off Bulger of a looming indictment. He was found guilty in 2002 on federal charges related to his partnership with Bulger. He is serving 40 years in prison in connection with a murder of a witness against Bulger.

Bulger’s attorney, J.W. Carney, argued in early motions in the case that Bulger had received immunity for his crimes from federal officials. U.S. District Court Judge Denise J. Casper ruled such a defense was not admissible. During his opening statement, Carney somewhat inexplicably said that Bulger was never an informant and that he had simply paid off police and FBI agents.

Kelly, the prosecutor, said, “Even though you will hear he didn’t like informants or rats, the evidence in this case will be that Bulger was one of the biggest informants in Boston.”

Bulger’s career in the city’s underworld ran parallel to his brother’s rise as one of the most powerful politicians in the state. William Bulger was the state’s Senate president for nearly two decades and later president of the University of Massachusetts.

But in 2003 William Bulger left U-Mass., and public life, following a battle with then-Gov. Mitt Romney over his loyalty to his brother. According to leaked testimony, William Bulger had told a grand jury that “it’s my hope that I’m never helpful to anyone against him.” He invoked his Fifth Amendment right against self-incrimination during the House committee hearings.

William Bulger was not in court Wednesday morning.

Bostonians have for decades been consumed with a question that showed up on T-shirts and book covers: “Where’s Whitey?” Although the FBI had been accused of not wanting to find Bulger, perhaps for fear he would disclose more corruption, the agency renewed efforts to find him several years ago.

There had been alleged sightings around the world, but it turned out Bulger and one of his longtime girlfriends had been living the life of retirees in Santa Monica, Calif. He was turned in by a former a neighbor, an ex-beauty queen from Iceland. She received a $2 million reward.

Carney said Bulger, then on the FBI’s most-wanted list, was not hiding in California. In fact, the lawyer said, he was living in “plain sight.” But Carney did not mention that Bulger was living under an assumed name, with false identification and dozens of weapons — and $800,000 in cash — stashed in the walls.

The story of Bulger’s extraordinary life is being turned into two movies, one directed by Barry Levinson, the other by Ben Affleck and Matt Damon, who chronicled working-class life in their home town in “Good Will Hunting.”