James Bulger, the older brother of former University of Massachusetts chief and State Senate president William Bulger, was born and raised in South Boston. As a kid, he gained the knickname "Whitey," which he detests, for his distinctive shock of light blond hair.

Bulger gained a reputation for bad behavior early on. Known as a teenager for vicious fights and wild car chases, he soon graduated to more serious crime, and spent nine years in prison during the 1950s and early '60s for a string of bank robberies.

By the early '70s, Bulger had teamed up with veteran mobster Stephen Flemmi and was muscling his way up the ranks of Somerville's Winter Hill Gang, the preeminent Irish gang in the Boston area. Bulger developed a reputation as a tough, savvy enforcer and ruthless killer.

In 1975, Bulger was enticed to sign on as an FBI informant by John Connolly, an up-and-coming young agent in the agency's Boston office and Bulger's childhood acquaintance from the South Boston housing projects. It was the beginning of a dark, entangling relationship between Boston's top criminals and top law enforcement agents.

Over time, tips from Bulger and Flemmi helped the FBI build a case against their number-one target, the Italian Mafia. In order to keep the insider information flowing, Connolly and his fellow agents allegedly helped Bulger and Flemmi elude the law by tipping the mobsters off to sting operations and protecting them from prosecution.

By the early '80s, federal agents had nabbed most of the Boston Mafia's top tier and had locked up Howie Winter, the boss of the Winter Hill gang, for fixing horse races. Bulger and Flemmi were left standing as the city's undisputed kings of organized crime. The pair built a drug-trafficking and racketeering empire based in Southie and were rumored to be responsible for dozens of gangland murders.

All the while, the mobsters met regularly with their FBI handlers, sharing jokes and gossip and even exchanging Christmas presents.

In the early 1990s, however, the honeymoon ended. John Connolly retired from the FBI and the agency dropped Flemmi and Bulger as informants and began targeting them. In 1995, federal racketeering and extortion charges were handed down against Bulger, Flemmi, and their partners. Bulger, tipped off by Connolly that an indictment was looming, disappeared and was on the run until June 22, 2011 when he was arrested in Santa Monica, Calif., with his long-time girlfriend, Catherine Greig. The couple had been living there in a rent-controlled apartment for at least 13 years, according to neighbors. The FBI confirmed the arrest of the fugitive just days after it announced a new ad campaign targeting women for tips about Greig, who was also a fugitive.

While Bulger was on the run for more than 16 years, he was spotted across the country, from Long Island to Louisiana to California. Before his arrest, the last confirmed sighting of him was in London in 2002, according to the FBI. Bulger was added to the FBI's 10 Most Wanted list in 2000 for 19 murders, and there was a $2 million reward for information leading to his capture — the largest amount offered by the bureau for a domestic fugitive.

Bulger originally was scheduled to go on trial in November 2012, but a federal judge ruled that month that Bulgers trial would begin on June 6, 2013.