Bulger both hired killers and killed on his own, with no remorse.
It is difficult to say with certainty when Bulger committed his first murder, as there could have been killings during the commission of his many previous crimes which were unsolved and unwitnessed. In 1971 Bulger was loansharking and working as a bookmaker for Donald Killeen, the leader of an organized crime group in South Boston which was involved in a turf war with another group, called the Mullens. Paul McGonagle was a member of the Mullens who irritated Bulger.
According to Kevin Weeks, Bulger was irritated with McGonagle because of the way he talked around the neighborhood, presenting himself as a more violent and dangerous criminal than he really was, and that was all it took for Bulger to decide to kill him. Bulger was in a car driving when he saw McGonagle driving towards him, and slowed, rolling down the window and calling out McGonagle’s name. When the latter drew abreast of him, he shot him in the face just before realizing that it wasn’t Paul McGonagle, but his brother Donald.
Donald wasn’t involved in any of the gang activities prevalent in South Boston and as such had no enemies. Realizing his mistake Bulger informed his partner and mentor, Billy O’Sullivan, that he had killed the wrong brother only to be told not to worry. According to Weeks, O’Sullivan shrugged it off by saying, “He wasn’t healthy anyway. He smoked. He would have gotten lung cancer.” O’Sullivan was later murdered by Paul McGonagle. Donald Killeen was murdered in the spring of 1972, a crime attributed to Bulger, but claimed by some to have been committed by Mullen gang members.
A truce in the turf war was mediated by the local Mafia, the Patriarca family, and the Winter Hill gang. Bulger was by then one of the few surviving members of the Killeen group, and he represented them at the mediation, which resulted in the Killeens and Mullens uniting under the Winter Hill gang. The truce, which occurred in 1972, put Bulger and the surviving Mullens in control of the criminal enterprises of south Boston, and any operators which were not under their umbrella were soon targets of shakedowns. Bulger wasted little time in removing the remaining members of the Mullens from the scene.
Bulger never hesitated to kill a perceived enemy and as all of the criminal element of South Boston were known to the authorities, Bulger used their knowledge to his advantage. He developed the method of performing a second murder to confuse the authorities over the motive for the first. In another incident, a Boston detective who had been threatened by a gangster was approached by Bulger, who informed the detective that he would take care of it. Later Bulger told the detective that the threat had been eliminated.