Convicted Boston mobster James “Whitey” Bulger deserves two life sentences for taking part in and orchestrating 11 murders in the 1960s and 1970s, prosecutors wrote to the judge determining the 84-year-old’s fate.

Bulger, who was found guilty of racketeering charges in August, is scheduled to be sentenced next week. In a sentencing memorandum filed Thursday in Boston federal court, prosecutors said the mob figure deserves no mercy from U.S. District Court Judge Denise Casper.

“There are no mitigating factors, and defendant Bulger has no redeeming qualities, which would justify any sentence below the one called for by the U.S. Sentencing Guidelines and the applicable case law and statutes,” prosecutors wrote in a sentencing memorandum filed in federal court in Boston, according to the Boston Globe.

Bulger was the leader of the Winter Hill Gang that operated in South Boston. With the help of a rogue FBI agent, the bureau turned a blind eye to his criminal activity because he was an informant supplying information about the Italian mob in Boston. The agent tipped him off about his impending arrest in 1992, leading Bulger to go on the lam for 16 years before being caught in Santa Monica, Calif. Bulger spent 16 years on the FBI’s Ten Most Wanted Fugitives list during that span.

Prosecutors cited some of the grisly details of the murders Bulger participated in and plotted in explaining why he deserves two life sentences.

"Bulger's horrific crimes and sadistic behavior (e.g., shooting Bucky Barrett in the back of the head at close range after hours of interrogation and then lying down on the couch to relax as his gang buried Barrett) demonstrate that he deserves no mercy at the time of sentencing," prosecutors wrote, according to Reuters. They said Bulger was among the “most violent and despicable criminals in Boston history.”

Bulger didn’t testify at his trial, calling the proceedings a “sham.” The trial was marked by the former Winter Hill Gang leader’s outbursts, including cursing at witnesses.