Boston (CNN) -- Pounding his fist on the witness stand Thursday, real-estate developer Richard Buccheri, 73, described the day he came face-to-face with Boston's alleged Irish mob kingpin James "Whitey" Bulger.
Bulger is charged in the deaths of 19 people during some two decades. He also faces charges of extortion, racketeering and money laundering.
He had called Buccheri to a meeting to discuss the positioning of a fence on a property Bulger associate Kevin Weeks wanted to buy, Buccheri said.
He said they had barely sat down when Bulger banged on the table and told Buccheri, "You know Rich, sometimes you should just keep your mouth shut. You know Kevin Weeks is like a surrogate son."
Buccheri's opinion on the positioning of the fence was not favorable to Weeks.
Raising two fingers to his mouth to demonstrate, Buccheri said Bulger "takes a shotgun off the table and sticks it in my mouth. Then he took it out, punched me in the shoulder and said, 'Richard you're a stand-up guy. I'm not going to kill you."
But then, he said, Bulger "puts a 45 to my head" and demands $200,000 in 30 days, "threatening to kill me and my family."
Buccheri said he cut a check for the 200-grand, which Bulger's henchman, Steve Flemmi cashed days later. Buccheri said he had to give a Braintree bank teller verbal permission to cash the gargantuan check.
Flemmi finished up his six days of testimony Thursday. He described a decades-long journey that included extortion, meetings with FBI agents and slayings.
Flemmi testified he was by Bulger's side for most of it, saying both were FBI informants. He described hundreds of occasions when he and Bulger met with FBI agents.
The defense suggested Wednesday that Flemmi would say anything to sweeten his deal with prosecutors and possibly get out of prison, even though the government has never raised that as a possibility.
Flemmi was arrested in 1995, was found guilty and was sentenced in 2001 to 10 years in prison for extortion and money laundering. In 2003 he pleaded guilty to 10 murders and was sentenced to life in prison.
Bulger attorney Hank Brennan asked Flemmi whether he hoped to get out of prison one day, and Flemmi said, "I'm still alive. There's always hope."
Brennan also highlighted Flemmi's relatively comfortable living conditions. "It's like the Club Med of federal facilities," he said.
"You really think so?" Flemmi responded, apparently incredulous, about the undisclosed prison.
Brennan also asked about an apparent delicatessen on the premises serving salmon, steak, and smoked oysters.
Flemmi denied such a place exists, saying, "If I fed some of that food to my dog, he'd bite me." He then complained about the July Fourth prison meal saying disgustedly, "The hotdogs were burned. The hamburgers were burned."
Flemmi was spared the death penalty on the 10 murder charge after agreeing to testify against Bulger and his disgraced FBI informant handler, John Connolly.
Authorities say Connolly accepted thousands of dollars from Bulger and his crew in payoffs and, in turn, tipped them off to law enforcement activity. Connolly was convicted of federal and state crimes and is serving 40 years in Florida.
Under Flemmi's plea deal, the government allowed him to keep numerous properties including a home, at least four condos and a coin laundry.
Despite Connolly's conviction and Flemmi's testimony, Bulger's lawyers have argued in this trial that he was not an FBI informant.
Authorities say Connolly, who was raised in the same housing projects as Bulger, cut a deal with the alleged mob figure in 1975. Bulger would give information about the Italian mob -- the FBI's prime target -- while Bulger, authorities said, got names of rival gang members and other informants who had dirt on him. He is accused of killing those people.
Without that FBI protection, prosecutors say, Bulger and Flemmi's reign of terror would not have been as successful or lasted as long as it did, from the early 1970s through the mid-1990s.
Bulger rose to the top of the notorious Winter Hill gang, prosecutors say, before he went into hiding for more than 16 years after the crooked FBI agent told him in December 1994 he was about to be indicted on federal racketeering charges.
He was captured in Santa Monica, California, two years ago, living under a false name with his girlfriend in an apartment in the oceanside city. The girlfriend, Catherine Greig, was sentenced to eight years in prison last summer for helping him evade capture.
At his arraignment in July 2011 he pleaded not guilty to the 19 murder charges and 13 other counts.
Through his lawyers, the 83-year-old defendant had argued he was given immunity by the FBI and a former prosecutor. The judge dismissed the claim, saying any purported immunity was not a defense against crimes Bulger faces.
Prosecutors plan to call two more witness Friday, and expect to rest their case on the 30th day of trial.
The defenses amended witness list, which was cut virtually in half to 32 witnesses last week, was whittled down to a potential 16 witnesses after Judge Denise Casper ruled some witnesses irrelevant and the defense withdrew a handful. The list is subject to further change.
Among those virtually certain to testify are four FBI agents who the defense says will testify Bulger was not an informant for FBI in Boston.
The government argued that Bulger is not "charged" with being an informant and the testimony could confuse jurors. But Casper said that, "given the centrality of the government's allegation of Bulger being an informant to all of the matters in this case, I think those are proper witnesses."
Also on the stand Thursday afternoon was bar owner Kevin O'Neil, one of the O's in "Triple O's Bar," an establishment that doubled as one of Bulger's many headquarters in the 1970s and '80s. O'Neil said he had Bulger on the payroll, but he was never an employee.
When prosecuting attorney Zachary Hafer asked why he was on the payroll, O'Neil responded, "He asked."
Hafer: "Why didn't you say 'No'"?
O'Neil: "I didn't think it was smart."
O'Neil testified that in Christmas of 1994 he got a call from Connolly, who said, "Get ahold of the kid because his friend has a problem."
In rapid-fire questioning, Hafer asked, The Kid?--"Kevin Weeks"; the friend?--"Jim Bulger"; the problem? --"I believe indictments."
O'Neil testified that he then saw Connolly talking to Weeks shortly after that call.
O'Neil said he never saw Bulger again after that day.
Prosecutors say Connolly tipped Bulger off to a 1995 indictment, causing Bulger to go on the run, landing himself on the FBI's top 10 most wanted list before being arrested in California.
Besides the slayings, Bulger is accused of using violence, force and threats to shake down South Boston's bookmakers, loan sharks and drug dealers. The Irish mob allegedly laundered its ill-gotten gains though liquor stores, bars and other property it owned in South Boston.
CNN's Gary Carter contributed to this report.