Model, actress and radio personality Pearl Thusi was in a car accident that left her and her daughte.
Prosecutor Edmundo Garrido said that Hendrik Cuacuas was hit in the head by a 9-mm bullet at a theatre in the rough neighbourhood of Iztapalapa.
Hendrik was watching the animated Disney film "Wreck-It Ralph" when he died Nov. 2, but the case didn't get any attention until his father went to the media this week.
The boy had gone to the movie with his father and 12-year-old sister.
Ballistics expert Anselmo Apodaca says a bullet passed through the building's laminate roof, then pierced a suspended ceiling and travelled to the upper right side of the child's head.