Louis Ruggiero in the hallway at Manhattan Criminal Court on Tuesday. Ruggiero, the son of "Good Day New York" anchor Rosanna Scotto, testified today as the prosecution's star witness in the murder trial of James Rackover. (Alec Tabak for New York Daily News)

With friends like these, who needs enemies?

James Rackover, on trial of the gruesome murder of a former party pal, once tried to blackmail his best bud — the son of Fox 5 morning host Rosanna Scotto — by threatening to release footage of his friend having sex with prostitutes, prosecutors said Tuesday.

Advertisement

The shakedown came to light as prosecutors and defense attorneys argued over how much of the twisted history between the two men could be revealed in court.

Scotto’s son, Louis Ruggiero, 24, a key witness for the prosecution, said he and Rackover, 27, often “partied” together and snorted cocaine.

Before attending rehab, he was doing an 8-ball of cocaine and $900 worth of painkillers a day, Ruggiero admitted.

Rackover lived in the same building as his “surrogate father,” 58-year-old wealthy jeweler Jeffrey Rackover, who prosecutors argue was really the younger man’s companion “masquerading” publicly as his dad.

Assistant District Attorney Antoinette Carter, arguing to get more of Rackover’s past behavior on the record, said he had once tried to blackmail Ruggiero over a major debt they had both racked up while running an illegal bookmaking business.

Rackover threatened to release footage of Ruggiero having sex with a prostitute on Jeffrey Rackover’s bed — which always had a camera rolling above it.

“The defendant threatened him and told him he would expose him by showing the videos to Mr. Ruggiero’s girlfriend,” Carter said.

Carter wanted to find out more about the story on redirect, but the judge shut that line of questioning down. Prosecutors were also unable to present evidence that both men tried to repay their debt by stealing from their parents — Ruggiero from Scotto and Rackover from the older man whose name he adopted as an adult.

Ruggiero, who is now an entertainment concierge in Los Angeles, testified Jeffrey Rackover and his high-profile mother, co-host on Fox-5’s “Good Day New York” were such close friends he used to call him his uncle.

He told jurors Monday that his friend Rackover had anxiously tracked him down at an Equinox Fitness Club on E. 61st St. the day after the murder to confess to killing and butchering Comunale.

Another party friend, Larry Dilione, 30, knocked Comunale out but Rackover said that “I gave him a few licks as well and I didn’t want a dead body in (my) living room so I slit his throat and I stabbed him,” according to Ruggiero’s testimony.

Rackover’s defense tried to poke holes in Ruggiero’s testimony Tuesday, noting that he’d twice failed to mention to the grand jury that his friend had admitted to stabbing Comunale. The medical examiner on Tuesday confirmed that Comunale died from stab wounds.