A veteran DC cop heralded as the first openly gay union chair and tasked with helping to protect President Trump allegedly groomed a teen boy before trying to have sex with him. Lt. Matthew Mahl, 47, had been communicating with a detective who was posing as a teen named “Nate” while staking out a Reddit site called “r/GayYoungOldDating, NBC News reported. Mahl — a special-operations officer whose duties included helping to provide security for Trump, Vice President JD Vance and other officials —