Doomsday mom Lori Vallow’s brother, Alex Cox, died of natural causes in December, the Maricopa County Medical Examiner said Friday after months of speculation about his death. Cox, who was found dead in his bathroom, suffered bilateral pulmonary thromboemboli or a blood clot wedged into an artery of his lung, the examiner’s office said. He also tested positive for Narcan, or naloxone, which is used to reverse an opioid overdose. The report listed contributing causes of death high blood pressure.

Cox is the older brother of Vallow, the 46-year-old doomsday-obsessed mother who is facing several charges in relation to her missing kids— 17-year-old Tylee Ryan Vallow and 7-year-old Joshua “J.J.” Vallow. The children have not been seen since September. Vallow married apocalyptic author Chad Daybell shortly after. Daybell’s wife Tammy died of unknown causes in October and Daybell declined an autopsy. Vallow’s estranged husband Charles Vallow also died around the same time. Cox claimed in July he shot Charles, who was divorcing Lori, in self-defense during a domestic dispute.