James "Whitey" Bulger found witness testimony amusing during his racketeering trial on Friday.

"Richard O'Brien recalled being summoned to a meeting at a Braintree hotel in the 1970s after one of his agents indicated he wanted to go into business for himself. O'Brien said Bulger told the man he had another business aside from bookmaking," according to USA Today.

O'Brien, 84, recalled asking about Bulger's side business. Bulger replied, "Killing (expletive) like you," O'Brien said.

Bulger "chuckled" in court after O'Brien told the story.

Bulger, 83, is on trial on charges of 32-count racketeering indictment that accuses the mobster of participating in 19 murders in the 1970s and '80s. Bulger is also faces charges of money-laundering and extortion.

Two bookies testified in court Friday that they were forced to pay Bulger and his Winter Hill gang monthly fees known as "rent" or "tribute" to stay in business. The bookies were also threatened if they attempted to go out on their own.

O'Brien had several jurors smiling at times as he told the court about his meetings with gangsters in the 1960s and '70s, including one meeting with New England Mafia boss Raymond Patriarca, according to USA Today.

"It was kind of a short meeting because it was the day (Teamsters President) Jimmy Hoffa was arrested, and they were all up in arms about that," O'Brien said on the witness stand.

James Katz, a bookie, reportedly testified that if anyone did not pay Bulger's gang, they could end up in the hospital. Katz told the court he paid $500 to $1,000 a month to the gang.

More of Bulger's former loyalists are expected to testify for the prosecution, including Stephen "The Rifleman" Flemmi, hitman John Martorano and former Bulger lieutenant Kevin Weeks.

Martorano, who admitted killing 20 people and served 12 years in prison, is expected to testify Monday.

Bulger was on the FBI's most wanted fugitives list after he fled Boston in 1994. He was captured in Santa Monica, Calif., in 2011, after almost 20 years on the run.