Marty Tankleff spent almost 18 years in prison after being wrongfully convicted of murdering his parents as a teenager in their Long Island home.
His case turned on an unsigned confession, allegedly coerced but eventually disavowed.
But for years, records show, prosecutors in the 1988 slayings case neglected to tell him and his lawyers about witnesses who pointed to a possible hitman. And, he alleged, they also knew that the man he had suspected was behind the killings had a history of hiring people to commit violent acts…