MARICOPA COUNTY, Ariz. — Alex Cox, the brother of Lori Vallow-Daybell, died of natural causes, according to autopsy results released Friday.
The Maricopa County, Arizona Medical Examiner concluded Cox died of a blood clot in his lung and heart disease.
Cox died suddenly in December, about three months after his niece and nephew - Tylee Ryan and J.J. Vallow - were last seen.
In March, the FBI and the Rexburg, Idaho Police Department released a photo of Cox, Tylee and J.J. taken at Yellowstone National Park last September, shortly before the two children were last seen.
In July 2019, Cox shot and killed Charles Vallow, Lori's estranged husband at the time. He claimed self-defense in the shooting and was not arrested.
Lori Vallow-Daybell has been in an Idaho jail since March, facing felony charges of desertion and nonsupport after she failed to bring Tylee and J.J. to Idaho authorities to prove they were safe. She is charged with two felony counts of desertion and nonsupport of dependent children under 18, and misdemeanor charges of resisting or obstructing officers, criminal solicitation to commit a crime and contempt of court.
Lori and her husband, Chad Daybell, are also under investigation for conspiracy, attempted murder and/or murder in connection with the October death of Chad's then-wife, Tammy Daybell.