Lawyers for John "Junior" Gotti said they received notification Friday from prosecutors that a former NYPD detective allegedly tied to the mob has pleaded guilty to federal charges. The nature of the charges facing Phil Barrone wasn't disclosed, according to Gotti lawyer Charles Carnesi. A spokeswoman for the U.S. attorney's office in Manhattan declined to comment when asked if Barrone had entered any plea. Word that Barrone, who left the force in the 1980s, has entered a plea raised the question of whether the former cop might be a cooperating witness in the Gotti trial, slated to begin Monday.