A Bronx private investigator has copped to bribing and intimidating witnesses to try to keep them from cooperating with authorities in a pal’s gun case, officials said Tuesday.

Charles Gallman, 55, admitted to helping Frederick Freeman — who was charged with a pointing a gun at his girlfriend’s brother — threaten the brother and his family in an attempt to stop them from testifying against Freeman.

Officials caught Gallman and Freeman scheming during wiretapped phone calls while Freeman was at Rikers.

Gallman still faces federal charges in Brooklyn for allegedly helping criminal defense lawyer Scott Brettschneider lie to prison officials about one of Brettschneider’s clients in a bid to cut time off the client’s prison sentence.

Under the terms of the plea deal in the gun case, Judge Joseph Zayas said he would sentence Gallman to one to three years in prison.

“Witnesses of crimes must be protected from outside interference that might affect their testimony,” Queens District Attorney Richard Brown said in a statement.

Freeman took a plea in the case in 2016 and is now serving his nine-and-a-half-year sentence.