Wednesday, July 22nd 2009, 4:00 AM

Burton Kaplan, the bespectacled Jewish gangster from Brooklyn whose turncoat testimony was pivotal in bringing the murderous “Mafia Cops” to justice, has died.

Kaplan, 75, was in the federal witness protection program and had been relocated outside New York State, sources told the Daily News. They said he died of natural causes.

The mob rat’s daughter, Deborah Kaplan, a respected Manhattan Supreme Court justice, declined to comment.

For years, Kaplan was the go-between for gangster Anthony (Gaspipe) Casso and NYPD Detectives Louis Eppolito and Stephen Caracappa, who passed confidential information to the crime boss and carried out hits for the Luchese crime family.

“Without Burt Kaplan’s cooperation, the full scope of their corruption and betrayal would never have been known,” said Mark Feldman, the former chief of the organized crime section for the Brooklyn U.S. attorney’s office, which prosecuted the dirty duo.

In 2004, Kaplan was suffering from prostate cancer and serving a 27-year sentence for marijuana trafficking when he was approached by an investigator from the Brooklyn district attorney’s office who convinced him to flip.

“I can’t honestly say I did this for my family,” Kaplan, a garment industry businessman, explained at the Mafia Cops’ trial. “I did it, in all honesty, because I felt that I was gonna be made the scapegoat in this case.”

Former NYPD Detective Thomas Dades, who was instrumental in cracking the case, said Kaplan was haunted by the murder of innocent victim Nicholas Guido, who was gunned down on Christmas Day 1986 by hit men acting on bad information from the Mafia Cops.

Eppolito and Caracappa were convicted of eight murders and are serving sentences of life without parole.

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