BOSTON (AP) — James “Whitey” Bulger’s former partner in crime returned to the witness stand Wednesday for a fifth day of testimony, with the defense harping on his role as an FBI informant while trying to discredit him as a liar.

Stephen “The Rifleman” Flemmi claims he and Bulger were secret FBI informants for years while they ran the city’s murderous Irish mob known as the Winter Hill Gang.

The 79-year-old confessed killer admitted Wednesday that he didn’t like it when other prison inmates called him a “rat,” but also took a verbal swipe at Bulger.

“I don’t think anybody likes it,” Flemmi said. “I don’t think Mr. Bulger likes it either.”

Bulger, 83, faces charges connected to 19 killings during the 1970s and ’80s while leading the notorious gang. He fled Boston in 1994 and was one of the nation’s most-wanted fugitives until his arrest in California two years ago.

Bulger attorney J.W. Carney Jr. said in court Wednesday that the defense is trying to show jurors that Bulger wasn’t a government informant to undermine the credibility of government witnesses who claim he was.

Carney said he also wants to call former FBI agents to testify about whether John Connolly Jr., a corrupt, former FBI agent who is now in prison, could have taken information from other informant files and put it in a file for someone else.

Assistant U.S. Attorney Brian Kelly argued it’s “flatly false” Bulger wasn’t an informant, and that the type of testimony the defense wanted to elicit could confuse jurors and waste time.

The defense continued to hammer away at Flemmi’s credibility Wednesday, getting him to admit that he’d lied under oath years earlier. Flemmi said that if he hadn’t, it would’ve exposed a corrupt relationship with the FBI and that wouldn’t have helped his defense.

But, the witness insisted, “I’m telling the truth now.”

Flemmi also identified diagrams that he drew for the FBI that detailed places where the rival Mafia gathered, and talked about conditions he faced in prison in Walpole, Mass., before he cooperated with the government and made a plea deal that kept him from facing the death penalty.

Flemmi said he lost 35 pounds, couldn’t sleep, couldn’t make phone calls, didn’t have a TV or a radio, didn’t have a chair to sit in when visitors came to see him, and spent 23 hours a day in a cell.

Flemmi previously had testified that Bulger strangled two young women and was a pedophile who had taken a 16-year-old to Mexico for a vacation with him.

The claim came as the defense questioned Flemmi about his own admission that he had oral sex with his girlfriend’s daughter, alleged Bulger slaying victim Deborah Hussey.

The defense had suggested that Flemmi, and not Bulger, strangled Hussey in 1985 because she was using drugs, getting arrested and dropping their names when she got in trouble.

The defense also pointed out inconsistencies in Flemmi’s testimony about both Hussey’s killing and the murder of Debra Davis, another Flemmi girlfriend.

Flemmi has testified that Bulger strangled both women with his hands, but Brennan said the witness testified during earlier trials that Bulger used a rope.

Flemmi insisted that the inconsistencies were due to “inadvertent mistakes” during his testimony.

After Wednesday’s testimony, Tommy Donahue, whose late father is among Bulger’s alleged victims, said Flemmi seemed like a “pansy” for someone who’s an admitted serial killer.

Donahue also called on police to say more about the death last week of Stephen Rakes, who had claimed Bulger forced him to sell him his liquor store and made no secret of despising the defendant. The day before his body was found, Rakes learned prosecutors wouldn’t call him to testify at the trial.

Rakes’ former lawyer, Paul V. Kelly, told The Associated Press last week that he had learned there was no wallet or vehicle found with the remains of Rakes, a 59-year-old Quincy resident.

Authorities have said there were no signs of trauma to Rakes’ body and they’re awaiting toxicology test results from his autopsy before ruling on his cause and manner of death.