By Jim Armstrong, WBZ-TV

BOSTON (CBS) – Every day of the Bulger trial, Tommy Donahue carries his father’s death certificate to court in his pants pocket.

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His father Michael was an innocent man, gunned down allegedly by James “Whitey” Bulger himself in 1982, when Bulger was aiming for someone else.

Today, former state medical examiner, Dr. Richard Evans, showed jurors in Bulger’s racketeering trial 19 individual death certificates — Donahue’s included — one of each grisly murder with which Bulger stands charged.

WBZ NewsRadio 1030’s Lana Jones reports

But it was Donahue’s killing that returned to the fore when another former FBI agent, Gerald Montanari, took the stand Monday afternoon.

Back in 1982, Bulger found out a man named Brian Halloran was talking to the federal agents about what he claimed was Whitey’s involvement in the murder of Oklahoma businessman Roger Wheeler.

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Those FBI tips were supposed to be secret, but corrupt agent John Connolly told Bulger and his crew. A short time later, both Halloran and Donahue were dead, in the same shooting.

Montanari says Halloran told him that if Bulger or his partner found out he was cooperating, they would “go to any extreme,” even if it meant killing bystanders.

Disgraced former FBI supervisor John Morris has already told jurors in this trial that he was the one who told Connolly about the perceived threat to Bulger that Halloran posed.

Then, when Bulger and partner Steve Flemmi are listed as suspects in the Oklahoma killing, they were brought into FBI Boston headquarters to pose for a picture, to be shared with investigators in Tulsa. In the photo, Bulger is smiling broadly. He and Flemmi wore business suits to the photo session.

The FBI at the time was well aware that these two men were suspects, but apparently kept using them as informants.

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“These are the guys who was coming to my house, questioning my mom,” Tommy Donahue said after court. “Knowing the whole entire time exactly what happened to my father, and they come and throw crap questions at my mother? You know, the government’s gotta do right by my family sooner or later.”