NEEDHAM, Mass. —Inmates in a federal prison knew about the impending transfer of notorious Boston gangster James “Whitey” Bulger to their facility in West Virginia, where he was killed within hours of his arrival, according to information revealed in a recent hearing.

A transcript from Monday’s detention hearing for Sean McKinnon, 36, includes quotations from evidence of a call between McKinnon and his mother prior to Bulger’s transfer to USP Hazelton in West Virginia from a prison in Florida in 2018. It also contains her testimony about that conversation.

The transcript offers new insight into a case where authorities have released only limited information. Officials have not revealed a possible motive for Bulger’s killing, which has raised questions about why the 89-year-old was moved to the prison nicknamed “Misery Mountain” and placed in its general population instead of more protective housing.

McKinnon was on federal supervised release when he was arrested Thursday in Florida on charges including conspiracy to commit first-degree murder. After Monday’s hearing in federal court in Ocala, Florida, a judge decided he will remain behind bars while he awaits trial.

During the hearing, prosecuting attorney Hannah Nowalk read quotes from a call between McKinnnon and his mother on Oct. 29, 2018. Bulger was found dead in his cell the next morning.

“We’re getting ready to get a — getting ready to get another higher profile person here tonight,” McKinnon said.

“You know who he is,” McKinnon also said. “No, I mean, you should know the name. Yeah, you know, you every [sic] — every heard the name Whitey Bulger?”

According to the transcript, McKinnon’s mother asked her son to, “Stay away from him, please.”

Nowalk also told the court about surveillance footage from the prison that showed two codefendants entering McKinnon’s cell around 6 a.m. The other men were Fotios “Freddy” Geas, 55, and Paul J. DeCologero, 48.

“They stayed in the cell for a few minutes, and then all three of them exited,” Nowalk said. “Freddy and Pauly entered Whitey Bulger’s cell, whereas Sean McKinnon is seen on the surveillance footage sitting at a table that faces Whitey Bulger’s cell.”

Geas and DeCologero were in the cell for roughly seven minutes, the transcript said.

Authorities say Geas and DeCologero struck Bulger in the head multiple times while McKinnon acted as a lookout. McKinnon is charged separately with making false statements to a federal agent. Prosecutors say he told federal agents he wasn’t aware of what happened to Bulger.

An inmate witness will also testify that DeCologero said that he and Geas “used a belt with a lock attached to it” to beat Bulger to death, Nowalk said.

Bulger was found dead at 8:07 a.m. on Oct. 30, 2018.

Bulger’s family has blamed the federal prison system for allowing Bulger, an elderly inmate who arrived at the prison in a wheelchair, to be attacked. In a statement, Hank Brennan, an attorney for Bulger’s estate told 5 Investigates: “We didn’t need affirmation to know that the system put a hit on James Bulger. The DOJ has hidden this confirmatory information from the public and Mr. Bulger’s family for four years but covetously spews these facts publicly when it serves its interest to deprive a person of liberty. The DOJ repeatedly proves it follows no moral compass and is strictly loyal to its own self-interest.”

Bulger, who ran the largely Irish mob in Boston in the 1970s and ’80s, served as an FBI informant who ratted on his gang’s main rival, according to the bureau. He later became one of the nation’s most-wanted fugitives.

Bulger strongly denied ever being a government informant. An intake screening form Bulger signed after arriving at Hazelton said he answered “no” when asked if there were any reasons he should be kept out of the general population and if he ever assisted law enforcement in any way.

McKinnon, who was Geas’ cellmate at Hazelton, pleaded guilty in 2015 to stealing a dozen handguns from a Vermont firearms dealer. He was moved to a halfway house in February before being released from there in July.

DeCologero, who was in an organized crime gang led by his uncle in Massachusetts, was convicted of buying heroin that was used to try to kill a teenage girl his uncle wanted dead because he feared she would betray the crew to police. The heroin didn’t kill her, so another man broke her neck, dismembered her and buried her remains in the woods, court records say.

Geas, a Mafia hitman, and his brother were sentenced to life in prison in 2011 for their roles in several violent crimes, including the 2003 killing of Adolfo “Big Al” Bruno, a Genovese crime family boss in Springfield, Massachusetts.

The Associated Press contributed to this report.