A Massachusetts man was sentenced to more than four years in federal prison for his role in the murder of James “Whitey” Bulger in a West Virginia prison in 2018.

Paul “Pauly” DeCologero pleaded guilty to a single charge of assault resulting in serious bodily injury at a federal court in Clarksburg, West Virginia, Thursday. In return, federal prosecutors dropped other charges included in the 2022 superseding indictment: conspiracy to commit first-degree murder and first-degree murder.

Chief District Judge Thomas S. Kleeh sentenced DeCologero to 51 months in federal prison, which is four years and three months. DeCologero was already serving a 25-year sentence handed down in 2006 after he was convicted of buying heroin used to try to kill a teenage girl.

DeCologero, according to the stipulations of the Thursday plea agreement, “served as a lookout” as another inmate, Fotios “Freddy” Geas, beat Bulger to death in his cell over several minutes just after 6 a.m.. When the infirm old Boston killer laid lifeless on the floor of cell 132, Geas and DeCologero placed him in his bunk and covered all but the top of his head with bedding.

About an hour later, prison staff saw “blood on Bulger’s head, and he was unresponsive,” the agreement states. “Staff attempted emergency medical treatment, but Bulger was pronounced dead at 9:04 a.m.

Bulger, who was in poor health, arrived to the prison from a different prison in Florida at about 8:30 p.m. the evening before

An autopsy revealed what was apparent on Bulger’s battered body: that significant blunt-force injuries to his head killed him. The blankets that covered his body, a crime lab found, contained DNA matching DeCologero.

DeCologero was not always described by authorities as a “lookout.” In the original indictment, prosecutors alleged that both Geas and DeCologero struck Bulger in the head multiple times while a third man, Sean McKinnon, served as a lookout.

A federal prosecutor during a detention hearing for McKinnon said that DeCologero had admitted to that “they collectively were the guys that killed Bulger” and that he and Geas had “used a belt with a lock attached to it” to beat Bulger to death over a roughly seven-minute period.

Court records show that all three men had agreed to take on plea deals. Plea change hearings for Geas and McKinnon — who is charged with lying to federal authorities — have yet to take place.