Prosecutors have filed additional charges against a strength and speed coach accused of a sexually assaulting children. Donald Kumar Davis, 33, of Nutley, was arrested on Sunday and served with the new charges — two counts of aggravated criminal sexual contact and one count of endangering the welfare of a child. Davis was first charged in the repeated sexual assault of a child on December 19, 2023. Investigators have since alleged that he had a second victim, resulting in the new charges. The investigation into Davis started on December 13, 2023, when someone called authorities and reported th…