After his December 10th passing, authorities took an educated guess about the cause.
Almost two months later, it's been officially determined that Michael Cavallari died of hypothermia, as initially suspected.
The autopsy report came out today from Utah's Grand County Sheriff's office, according to TMZ.
Cavallari went missing after Thanksgiving, and his body wasn't found until almost two weeks later in the desert, three miles from the nearest road.
His car was still running when officials came across it in a ditch, and the theory is that Cavallari got out of the car and went walking for help.
Unfortunately, December temperatures in that area of Utah dipped into the teens at night, and only reached thirty during the day.
No evidence of drugs or alcohol was found, despite Cavallari's publicized struggle with substance abuse and run-ins with the law.
On November 23rd, just a few days before his disappearance, Cavallari was arrested for threatening a woman with a gun.
Shortly after being released from police custody, Cavallari left Los Angeles. Where he was headed remains unknown.
In early January, Kristin Cavallari made reference to her older brother's death, as well as the birth of her daughter, Saylor.
"2015 brought my sweet, baby girl but it also took my brother's life," Cavallari wrote.
"Hoping for no extreme highs and lows this year."