(CNN) One of two suspects being investigated in the prison death of former mob boss James "Whitey" Bulger is a Massachusetts man named Fotios "Freddy" Geas, the Boston Globe and The New York Times have reported.
Geas is serving a life sentence at Hazelton prison in Bruceton Mills, West Virginia, according to the Federal Bureau of Prisons and online records. Bulger was killed at the prison on Tuesday, a day after his transfer to the facility.
The Times story said Geas was moved to solitary confinement after the killing.
The Globe and Times stories cited unnamed sources with knowledge of the investigation.
Bulger, the notorious and much-feared former boss of the Irish mob in Boston, was found unresponsive at 8:20 a.m., according to a statement from the prisons bureau. He was pronounced dead by the Preston County medical examiner after failed lifesaving measures. He was 89.
No staff or other inmates were injured, the prisons bureau said.
The FBI and US Attorney's Office are investigating the death as a homicide.
According to a New York Daily News story from September 2011, Geas, of West Springfield, Massachusetts, was given a life sentence for the 2003 murder of a crime boss and another man they thought was an FBI informant. He is now 51.
Bulger, who eluded federal authorities for more than 16 years before his arrest in June 2011, was serving the rest of his life in prison for a litany of crimes that included his role in 11 murders.
Before he went on the run, Bulger had been a longtime FBI informant.
The US Penitentiary Hazelton is a high-security facility that houses 1,270 male offenders.