The driver found shot to death after he struck and killed two young brothers in Alvin Friday night was a homicide victim, the Harris County Medical Examiner has ruled.

Jose Banda, 20, was found unconscious behind the wheel of his car with a gunshot wound to the head. He was flown to Memorial Hermann Hospital where he later died.

Investigators didn’t find a weapon at the scene, and they’re still trying to figure out who killed Banda.

Brazoria County sheriff’s investigator Dominick Sanders says witnesses heard gunshots three minutes after the first 911 call reporting the accident.