Michael Brea, 31, who has been charged with murder, howled, "Sinner! Sinner! You never accepted Jesus!" at his mother Yannick before killing her, neighbors and police told New York's Daily News.
He screamed at her to repent and later told psychiatrists at Bellevue Hospital that he had seen the devil in her, according to the New York Post.
Alerted to the commotion by neighbors, police broke down the apartment door at around 2 a.m., tasered Brea and arrested him, and later charged him with second-degree murder and criminal possession of a weapon.
Brea's uncle, Serge Marcel, told the New York Times that his actor nephew was "a very nice kid, a gentle kid."