On the 30th anniversary of the Son of Sam murders, Gotham’s WCBS has locked up an exclusive sit-down interview with convicted serial killer David Berkowitz.In the interview, Berkowitz reveals new developments of the case to reporter Scott Weinberger at the upstate New York prison where he’s serving a 365-year sentence. Now a born-again Christian, Berkowitz talks about finding God and goes on the record for the first time about his communication with Neysa Moskowitz, mother of his last murder victim, Stacy Moskowitz. Weinberger also speaks with retired-NYPD Sgt. Joseph Coffey — the detective who took Berkowitz’s detailed confession — who relates confession details and describes events linked to the late 1970s murders. Three-part series airs May 7-9 at 11 p.m.