BOSTON (CBS) -- Kevin Weeks lived up to his billing in federal court on Tuesday.
In the morning, he said James "Whitey" Bulger was once his mentor and like a big brother.
By afternoon, he was screaming obscenities at him from the witness stand.
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Before that, though, Weeks detailed how Whitey ran his criminal enterprise.
He described how Bulger would write out huge Christmas lists full of pricey gifts that he bought in order to pay off police, state troopers, and federal agents who gave him secret information.
Weeks said Bulger had a famous line at that time of year: "Christmas is for kids and cops."
Weeks also watched Bulger stuff envelopes with thousands of dollars in cash for FBI agent John Connolly and others.
Bulger once bragged to Weeks he had corrupted six FBI agents with his bribes.
Weeks also told jurors about three murders he watched Bulger commit from 1983 to 1985.
Those were the bodies buried in Dorchester to which Weeks led investigators when he started cooperating in 2000.
Weeks admitted to a long long list of crimes, but was adamant - he's no rat.
That's what lead to the heated exchange.
Weeks is clearly still furious that Bulger and Steve Flemmi were informants the whole time.
WBZ NewsRadio 1030's Lana Jones reports
Bulger, Weeks Swear At Each Other During Trial
Weeks: We killed people that were rats and I had the two biggest rats right next to me.
Bulger: You suck!
Weeks: [expletive] you, okay?
Bulger: [expletive] you, too!
Weeks: What do you want to do?
Judge Denise Casper had to raise her voice as well to calm everyone down.
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