Maricopa County Medical Examiner rules brother of Lori Vallow died of natural causes

FOX 10 has learned that the Maricopa County Medical Examiners Office has made a ruling on the death of the brother of Lori Vallow.

Lori Vallow is the mother of two missing children with Arizona ties. Joshua "JJ" Vallow and Tylee Ryan were last seen in September 2019. The disappearances have uncovered a complicated sequence of events related to Lori and her new husband, Chad Daybell, including details surrounding the death of Lori's former husband, Charles Vallow, details surrounding the death and subsequent burial of Daybell's former wife, Tammy Daybell, and details of unorthodox religious beliefs, including allegations of cult membership.

RELATED: Click here for an interactive timeline of events surrounding the case

In late January, Idaho authorities say a child protection action was filed on behalf of JJ and Tylee, and that a court has ordered Lori to physically produce the two children to the Idaho Department of Health and Welfare in Rexburg within five days of being served with the order. Lori ultimately failed to obey the court order. She was subsequently arrested in Hawaiiextradited to Idaho, and made a court appearance there.

Joshua Vallow (left) and Tylee Ryan (right) (Photo Courtesy: Rexberg, Idaho Police Department)

Charles Vallow was killed in 2019 following a shooting at a Chandler home. According to Chandler Police officials at the time, Vallow was shot by his brother-in-law, who we now know is Alex Cox. Cox died in December 2019.

According to the medical examiner's report, Alex Cox's death was deemed a natural death, with the primary cause of death being listed as "Bilateral Pulmonary Thromboemboli." Atherosclerotic and Hypertensive Cardiovascular Disease being listed as contributory causes of death.

According to the Mayo Clinic, a Pulmonary Embolism is a blockage in one of the pulmonary arteries in a person's lungs.

A blood clot was reportedly collected, inventoried and released to detectives at the time of the examination, according to the Medical Examiner's report.

According to the Medical Examiner's report, Cox reportedly complained of chest pain and shortness of breath before he was found unresponsive on his bathroom floor on December 12. Cox's wife, who has been identified as Zulema Pastenes in a story aired by FOX 10 in February, reportedly said Cox had no past medical history, and was not taking any routine medications.

Alex Cox (left) (Photo Courtesy: Mary Tracy)

FOX 10 has also obtained Cox's toxicology report, which shows that Cox tested positive for having naloxone in his system.

According to the Substance Abuse and Mental Health Services Administration, which is a part of the U.S. Department of Health and Human Services, Naloxone is a medication approved by the Food and Drug Administration to prevent overdose by opioids such as heroin, morphine and oxycodone.

FOX 10 has obtained a statement from attorneys representing Cox's family, which reads, in part:

"With a degree of vindication, the family hopes that the confirmation of this truth will help all to step back, take a breath, and allow the truth to unfold throughout the process,"