On 29 January 2008 Mullis drove his car with his three-month-old son Alijah James in the backseat after he argued with his girlfriend Caren Kohberger. After he parked his car Mullis proceeded to assault his son sexually. When Alijah cried, Mullis strangled the infant, followed by stomping on his head several times, crushing his skull and leading to his death. After he killed Alijah, Mullis disposed of the body by throwing it at the roadside around Seawall Boulevard, Galveston.