The 5-year-old Texas boy reported missing last month before his body was found in a motel room with his father’s girlfriend died of blunt head trauma, an autopsy has revealed. Officials in Harris County have now officially ruled that Samuel Olson’s death was a homicide. “The cause of his death is homicidal violence with blunt head trauma,” the Harris County Institute of Forensic Sciences announced Tuesday after the completion of his autopsy. Prosecutors have said they expect to file additional charges against Theresa Balboa, the girlfriend of Samuel Olson’s father, who is currently being held on a charge of tampering with evidence, a human corpse. Balboa, who tearfully spoke to local media outlets to ask for help in finding the 5-year-old after he was reported missing late last month, is said to have enlisted the help of her roommate in hiding the boy’s body on May 10, weeks before police were alerted to his disappearance. Court documents show that investigators believe she was scheming to leave Texas with the boy’s body when a tip led officers to the motel where she was staying with a plastic tote containing his remains.