Mickey Marcello is Reluctant Witness in Deputy US Marshal John Ambrose Trial

FBI recordings caught brothers James and Michael Marcello anxiously discussing information in 2003 that their Chicago Outfit associate Nicholas Calabrese might testify against them and others.

On Thursday, Michael "Mickey" Marcello was on the witness stand in Chicago's federal courthouse, reluctantly reliving those undercover recordings in the trial of Deputy U.S. Marshal John Ambrose.

Wearing an orange prison jumpsuit and thick glasses, Marcello, 58, squinted at transcripts of several recorded conversations with his brother and deciphered the vague codes and signals they used to furtively discuss Calabrese's enrollment in the witness protection program.

Marcello testified that he learned of Calabrese's cooperation with law enforcement from reputed mob figure John "Pudgy" Matassa Jr.

Ambrose is on trial on charges that while twice guarding Calabrese, he leaked Calabrese's cooperation to a family friend with alleged mob links, knowing the sensitive information would end up in the Outfit's hands.

Marcello denied directly knowing Ambrose or knowing that Ambrose was allegedly the source to the mob of Calabrese's cooperation.

When asked who he was referring to on one undercover recording when he identified the source as Calabrese's "baby-sitter," Marcello said, "The guy that watches him."

Marcello testified that Matassa indicated that the original source was in law enforcement. But Matassa said he himself was receiving information from another man named "Billy," Marcello said.

Marcello said that he presumed that referred to William Guide, a former Chicago police officer convicted in the Marquette 10 police corruption trial in the 1980s. Guide was a close friend of Ambrose's father, Thomas, who was also convicted in that prosecution and died in prison. But a key 2003 video recording in which the Marcello brothers discuss the source's ties to the Marquette 10 defendants, the initial clue that led authorities to investigate Ambrose, was belatedly removed from evidence Thursday by U.S. District Judge John Grady.

Grady reversed his earlier decision to allow the videotape as evidence even though the jury had already viewed it twice during the trial. "I apologize for making a mistake," said Grady, ordering the jury to ignore that particular videotape and hand in transcripts of that tape.

Prosecutors have argued that Ambrose leaked details of Calabrese's cooperation to Guide with the knowledge that it would reach organized-crime figures. Ambrose's attorneys have admitted that Ambrose talked to Guide about protecting Calabrese but contend he had no criminal intent.

Marcello, serving an 8 1/2-year sentence on racketeering and conspiracy convictions, spent more than five hours on the stand, responding to most questions with clipped, one-word answers. When questioned about his own organized-crime ties or the rank or status of other Outfit figures, including his brother James, he became visibly uncomfortable, stammering answers and pleading ignorance.

Outside the courtroom, Marcello's lawyer, Catharine O'Daniel, said that her client had testified only because he was granted immunity and threatened with an additional sentence for contempt if he did not appear. "He is not here willingly," O'Daniel said. "He's as willing as I am whenever I go to get a root canal."

Thanks to Robert Mitchum