The detail emerged as Monacello resumed his turn as a star witness in the racketeering trial of 73-year-old Ligambi and six codefendants.
Opening what could be days of cross-examination, Ligambi's lawyer tried to portray Monacello as a serial liar who was jealous of the defendants and would say anything prosecutors wanted to hear to avoid or reduce a prison term.
The Blavat threat emerged when jurors were shown a video of a September 2009 meeting between Ligambi and Monacello. The meeting was captured by a Fox29 film crew that had been secretly shadowing Monacello on a day he happened to visit Ligambi. The video showed the two men talking outside Ligambi's house, with the older man gesturing angrily.
The video didn't include audio. Monacello said Ligambi was complaining about the magazine story and Blavat, long known as the Geator with the Heater.
"You didn't take him seriously for a minute that he wanted to rub out the Geator, did you?" defense lawyer Edwin Jacobs Jr. asked.
"Hey," Monacello replied, "anytime he said he wants to kill anybody, I take him seriously."
Reached Tuesday by phone, Blavat said he wasn't the source of the magazine story and he was unaware of the threat.
"I grew up with these guys. I know Joe. I never heard it," he said.
During most of his two days of testimony, the well-coiffed, nattily dressed Monacello came across a confident witness, at times bordering on cocky.
He described himself as a businessman who owned seven fitness training schools, a restaurant and bar, but who also helped oversee Delaware County gambling, bookmaking and loan-sharking operations for George Borgesi, an alleged captain and nephew to Ligambi.
He also wasn't afraid to flash a gun or smash a skull. According to Monacello, he suffered the index finger injury - the one that led to his nickname - during a 1988 street fight with three guys after one grabbed his girlfriend's rear end.
He was loathe to cooperate, Monacello said, but did so because he believed the mob bosses wanted him dead. He pleaded guilty to charges in 2011 and will be sentenced after the trial ends.
"There's a fine line between me sitting here and there," he said, pointing to the defense table.
Theirs wasn't a loving crime family, according to Monacello. Bent Finger Lou acknowledged plotting to kill one captain, Martin Angelina, and had mounting distrust of Ligambi.
He said he also knew that the mob boss and Borgesi hated each other.
"Joe said he hopes his nephew does 100 years (in prison)," Monacello testified. "The nephew wants to choke his uncle."
Jacobs hammered the turncoat about whether he had perjured himself or embellished testimony about his criminal history and dealings with the defendants.
Jacobs pointed to Monacello's description of an assault on a contractor doing renovation work for Ligambi. Last year, Monacello told a grand jury he kicked the victim once in the chest. During this trial, testified that he kicked the man twice in the face.
Monacello dismissed the discrepancy as irrelevant. "That says once, I'm saying twice," he said, looking at the grand jury transcript. "Why would I lie about that?"
"I don't know," Jacobs retorted, "maybe to get a good deal?"
Monacello also denied the lawyer's claim that he once told a neighbor that he should be the head of the Philadelphia mob.
"Never," Monacello said.
But he didn't deny his relationships with ranking mobsters were frayed.
According to Monacello, Angelina stole from him by taking $11,000 from a man who owed Monacello $20,000, then telling the debtor that his debt was erased. Monacello wanted revenge.
"As a man, there are certain things you can live with and certain things you can't," he said during questioning by Assistant U.S. Attorney John S. Han. "And I wasn't gonna let Angelina rob me."
Monacello said he decided he would severely beat Angelina. But then an associate, Frank "Frankie the Fixer" DiGiacomo, persuaded him to hire two hit men to kill Angelina for $2,000.
Monacello didn't know DiGiacomo was wearing a wire for state police investigators.
The attack never happened but the assassination plot was detailed in state charges lodged against Monacello in 2009.
After that case went public, Monacello said, he expected mob retaliation. The morning after his arrest, he said, Ligambi knocked on his South Philadelphia door.
The mob boss told Monacello all would be fine, not to worry.
"He does this Academy Award-winning speech in front of my family: Don't worry about it," Monacello said.
In a gesture that stirred murmurs in U.S. District Judge Eduardo Robreno's courtroom, Monacello then turned and began clapping as he smiled at Ligambi.
"Academy Award, Joe," he said.
Still, Monacello pleaded guilty to the state charges and was sentenced to 11 1/2 to 23 months. He was indicted on the new federal charges in May 2011.
He said he decided to cooperate because he believed he would be killed because of his beef with Angelina. He assumed Ligambi and Angelina didn't do it because they were waiting for Borgesi, his crew chief, to be released from prison.
"These are the mob rules," Monacello told jurors. "They didn't do anything to me, because he [Borgesi] brought me in. He was gonna kill me when he was getting out."
It wouldn't have been right away, Monacello said. That wasn't Borgesi's style.
"He explained to me in the past, he's hung out for people for months before he killed them," the witness said. "Then, one night, I would've gone out and I just wouldn't have come home."
Contact John P. Martin at 215-854-4774, at email@example.com or follow @JPMartinInky on Twitter.