'Whitey' Bulger, Ex-Ally Stephen 'The Rifleman' Flemmi Exchange Curses in Court

July 18, 2013 — -- U.S. Marshals stood between James "Whitey" Bulger and his former friend, Stephen "The Rifleman" Flemmi, as the two alleged mobsters and fellow FBI informants faced each other for the first time since 1994 in a federal courtroom.

"The marshals made sure they couldn't make eye contact,'' Mike Donahue, who has been in the court for all 24 days of testimony, told ABC News.

Donahue's father, Michael Donahue Sr., was one of Bulger's alleged victims, an innocent father of three shot dead in 1982.

The lack of eye contact didn't stop Flemmi from snarling at Bulger as the jurors rose to leave the courtroom.

"Mother*****r!" Flemmi told Bulger.

"Go f*** yourself,'' answered Bulger.

Bulger has exchanged obscenities with a former crony in court before, earlier blowing up with his alleged former right-hand man, Kevin Weeks.

THE BIGGEST RAT: BULGER, PAL TRADE CURSES

Flemmi was only on the stand for approximately 10 minutes before court was adjourned for the day. Among the few questions federal prosecutor Fred Wyshak asked Flemmi was for him to characterize his relationship with Bulger.

"Strictly criminal,'' Flemmi answered.

Wyshak asked Flemmi to characterize Bulger's personality.

"Overbearing,'' Flemmi answered. "Forceful."

Then Wyshak attacked Bulger's claims via his defense attorneys that he was not a top echelon informant for the FBI, asking Flemmi, "Was Mr. Bulger an FBI informant?"

"Yes," Flemmi answered.

"Were you present with Mr. Bulger when he gave information to the FBI?" Wyshak asked.

"Yes,'' Flemmi answered. "Hundreds of times."

FULL COVERAGE OF THE JAMES BULGER TRIAL

The standoff, after Flemmi's brief testimony, between the men who allegedly were the most powerful crime lords in Boston was a dramatic end to a dramatic day in the Bulger case. It came on the same day that a potential government witness in the case, Stephen "Stippo" Rakes, was identified as the man found dead at the side of a road in Lincoln, Mass., Tuesday night.

More on the death of Stephen "Stippo" Rakes.

Rakes was last seen by other alleged Bulger victims in the courtroom Tuesday afternoon. He sent a text message to Tommy Donahue, another Donahue son, at 2:31 p.m. Tuesday afternoon, furious that he had been dropped from the government's witness list.

"He was upset that he wasn't going to get to tell his side of the story,'' Donahue told ABC News. "He had waited for a long time for his day in court, and now he is not going to get it. I don't think it was something that he would commit suicide over there. There is something wrong with this, really wrong."

READ MORE: Bulger victims speak

Added his mother, Patricia Donahue, who has been with her three sons, Mike, Tommy and Sean, every day: "We have become like a family, all the Bulger victims. Stephen Rakes was a good man. It's a sad day, and it makes me worry about what could happen to my boys."

Donahue said that between Flemmi and Bulger swearing at each other and "looking like two rams about to charge each other" and Rakes' death, she has become nervous for the first time about what her family is up against.

"It really has become unnerving,'' she told ABC News.

SLIDESHOW: Whitey Bulger's weapons and stash