How did a potential Whitey Bulger witness die? Boston buzzing.

The mysterious and sudden death of a man who had waited decades to testify against James “Whitey” Bulger has set Boston buzzing with memories of Mr. Bulger’s heyday and questions over the circumstances of his death.

Stephen Rakes, who claimed he and his then-wife were forced at gunpoint to sell their liquor store to Bulger in 1984, was found in the woods of Lincoln, Mass., on Wednesday, a day after prosecutors removed him from their witness list.

An autopsy revealed no obvious signs of trauma, according to the Middlesex District Attorney’s Office. Authorities are awaiting the result of toxicology tests, which typically take several weeks to complete, to determine a cause of death.

The circumstances of the death are considered suspicious, an unidentified law enforcement official told New England Cable News, and authorities are considering whether he died elsewhere before being brought to Lincoln, The Boston Globe reports.

Family members denied that Mr. Rakes would take his own life after being removed from the prosecution’s witness list Tuesday.

“I can assure you my ex-husband did not commit suicide,” Rakes’s former wife, Julie Dammers, told the Globe.

“We have more questions than answers,” she said. “We are just in limbo right now. We’re all in complete shock.”

Rakes was a vocal critic of Bulger leading up to the trial and attended the trial every day through Tuesday, when he was last seen there. Though he was a potential witness, the judge had agreed to exempt alleged victims and their families from the usual sequestration order, which keeps all witnesses out of the courtroom before their testimony. 

Rakes was eager to get on the witness stand, according to Tommy Donahue, son of alleged Bulger victim Michael Donahue. But prosecutors told the judge Tuesday who their remaining witnesses would be, and Rakes wasn't among them.

"He said he wanted to get up there and tell his side of the story," Mr. Donahue said Thursday.

It’s not yet clear why prosecutors decided not to have Rakes testify, but it’s probably due to the testimony of Kevin Weeks, a self-described former protégé of Bulger who gave a slightly different account of what happened with the liquor store. Prosecutors would be hesitant to bring another witness who could question the credibility of Mr. Weeks, legal analysts say.

Weeks denied that the gang forced Rakes to sell the store, saying Rakes had agreed to an offer from Bulger to buy the store for $100,000.

He said when they arrived at Rakes's house to close the deal, Rakes said his wife didn't want to sell the store and complained about the selling price.

"He was trying to shake us down," Weeks said from the witness stand.

Weeks said he pulled a gun out of his waistband and put it on a table, in front of Rakes's two young daughters, who were in the room. One of the girls was bouncing on Bulger's lap and reached for the gun, and Bulger told Weeks to put it away.

Bulger told Rakes that he couldn't back out of the sale, and they made the deal, according to the testimony. 

Rakes was present for the testimony and later disputed the account, saying he was forced to sell the liquor store. 

"Kevin continues to lie, as usual, because that's what he has to do," Rakes said that day. "My liquor store was never for sale – never, never, never." 

For family members of Bulger’s alleged victims, the news of Rakes’s death was particularly disturbing.

“I hope he wasn’t murdered,” Steve Davis, the brother of a woman Bulger is accused of killing, told The New York Times. “It brings you back to the early ’80s,” he said, referring to the frequent murders by Bulger’s gang.

Bulger, the former leader of South Boston's mostly Irish-American Winter Hill Gang, spent 16 years on the run, becoming one of the FBI's Ten Most Wanted before authorities captured him and his girlfriend in California in 2011. He is charged with participating in 19 murders but maintains his innocence.

• Material from the Associated Press was used in this report.