UNIVERSITY HEIGHTS, the Bronx —A grand jury declined to indict the teen accused in the choking death of his mother’s abusive ex-boyfriend, court officials said Monday.

Luis Moux, 18, was charged with manslaughter in August after he allegedly choked his mother’s ex-boyfriend to death, police said. The teen spotted Stanley Washington beating his mother inside their Bronx apartment.

The 43-year-old ex-boyfriend showed up at the University Avenue apartment around 4:30 a.m. to talk to the mother and allegedly beat the 37-year-old woman, police said.

Moux heard what has happening and rushed out of his bedroom, pulling Washington off of his mother, police said. He allegedly choked the man to death.

Police sources said the mother, who had briefly passed out, woke up to sight of her son standing over her ex-boyfriend.

Washington had 26 prior arrests, police sources said. Two of them were for instances of domestic violence against the Moux’s mother.