A Bronx ex-con was charged with murder after his elderly mom was found fatally battered with a black eye in their apartment this week, cops and law enforcement sources said. 

Melvin Arias, 57, was arrested Tuesday evening in connection to the slaying of his mom Francisca Trinidad, 79, who was found unconscious and unresponsive inside the apartment on Grand Concourse near East 156th Street in Concourse Village around 10:30 p.m. Monday, police said.