Federal investigators say they believe a second suspect was involved in the killing of mob boss James “Whitey” Bulger, the Boston Globe reports. Law-enforcement sources cited by the Globe say Paul J. DeCologero, a member of an organized-crime group involved in the dismemberment of a teenage girl, is believed to have teamed up with Mafia hitman Fotios “Freddy” Geas to beat Bulger to death in his cell in West Virginia this week. Former lawyers for Geas and a private investigator who worked for him have said he likely targeted Bulger for his role as an informant for the FBI, though it was not immediately clear what motive DeCologero would have had. DeCologero is serving a 25-year sentence for racketeering and the conspiracy that resulted in the 1996 murder of 19-year-old Aislin Silva. A group led by DeCologero’s uncle cut up and left Silva’s body in a dumpster out of fear she was planning to cooperate with police. Geas and DeCologero reportedly never crossed paths in their respective crime circles, but they are said to have become acquainted in prison. Their suspected involvement in Bulger’s murder raises questions about why Bureau of Prisons officials placed him in general population before they could determine whether any other inmates posed a threat.