BOSTON — A prosecutor called James “Whitey” Bulger a “little sociopath” Wednesday as he urged a judge to sentence the infamous South Boston gangster to life in prison. Bulger himself declined to speak.

“The defendant has committed one heinous crime after another,” said Assistant U.S. Attorney Brian Kelly. “The carnage that he has caused is grotesque.”

Bulger, now 84, was convicted in August in a broad indictment that included racketeering charges in a string of murders in the 1970s and 1980s, as well as extortion, money-laundering and weapons charges.

At least a dozen family members of people who Bulger was involved in or accused of killing spoke Wednesday.

The first to do so was Sean McGonagle, the son of Bulger victim Paul McGonagle. He called Bulger “Satan,” a “domestic terrorist” and a “sad, lonely and irrelevant old man.”

Several family members of victims also condemned the Boston office of the FBI and the Justice Department for corruption that allowed Bulger to continue his reign of terror for years.

“My family and I have nothing but contempt for you,” said David Wheeler, the son of Roger Wheeler, an Oklahoma businessman who was shot between the eyes after a round of golf at a Tulsa country club.

Bulger, wearing an orange prison jumpsuit, stared down at the defense table and mostly did not look at victims’ relatives as they spoke. He was given the opportunity to speak but declined.

His attorneys said he refused to provide any information to probation officials preparing a report for Judge Denise Casper, who will sentence him Thursday. Attorney J.W. Carney Jr. said he would make no sentencing recommendation because his client believed his trial was a sham.

Bulger also called his trial a sham in August after he was not allowed to use as a defense his claim that a now-deceased federal prosecutor gave him immunity to commit crimes. He did not testify.

The federal jury that convicted Bulger found prosecutors proved he played a role in 11 of 19 murders.

Jurors found the government had not proven Bulger participated in seven other killings and were unable to reach a verdict in another. But Casper ruled Wednesday that relatives of all 19 people could speak at the sentencing if they wanted, despite objections from Bulger’s attorneys.

Bulger, the former head of the Winter Hill Gang, fled Boston in 1994 ahead of an indictment and spent more than 16 years as a fugitive before being captured in Santa Monica, Calif., in 2011.