Cause of death sought after body believed to be Kristin Cavallari's brother found

SALT LAKE CITY, Utah -- A medical examiner will perform toxicology and other tests to determine what killed the person believed to be NFL quarterback Jay Cutler's brother-in-law, who was found dead in a steep and rocky area in an isolated part of southern Utah.

Authorities discovered the body Thursday, nearly two weeks after a rancher found Michael Cavallari's car abandoned near the area. Cavallari, 30, is reality TV personality Kristin Cavallari's brother.

The Utah medical examiner is working to confirm the identity and determine the cause of death, a process that could take as long as two months, Grand County Sheriff Steven White said.

The remains were near the bottom of a steep hillside filled with boulders, about 3 miles northwest of where Michael Cavallari's car was discovered the morning of Nov. 27.

There were no bullet holes, stab wounds or other signs of foul play. It's now up to the medical examiner to determine how he died, with toxicology reports certain to play a factor, White said.

Medical examiner officials were not immediately available for comment Friday.

Frigid weather in the area might have been a factor, White said. Nighttime temperatures were at or below freezing around the time the car was found against a small embankment.

"I don't know what his mental state might have been, with possible hypothermia," White said.

Kristin Cavallari said she was heartbroken in an Instagram post Thursday. She posted a picture herself and her brother as children and wrote that "Mikey" had a good heart and always made her laugh.

"I'm at a loss for words, but I know u are in a better place and finally at peace," she wrote. "I love u so much RIP."

Authorities had been searching for Michael Cavallari since his car was found with the engine running and the air bag deployed the day after Thanksgiving off a dirt road some 200 miles south of Salt Lake City.

Evidence shows the 2014 Honda Civic hit a couple of big rocks and washes, likely causing the air bag to deploy, White said. Michael Cavallari's cellphone and laptop were inside.

Investigators believed he was just passing through Utah, but they didn't know where he was headed.

Michael Cavallari was arrested in Southern California on an allegation of making threats four days before his car was found about 5 miles from Interstate 70 in Utah. He bailed out of jail Nov. 25.

Michael Cavallari was single and had no kids, White said.

His sister rose to fame in the mid-2000s when she appeared in the MTV reality series "Laguna Beach" and "The Hills." She is married to Cutler, who starred at Vanderbilt and now plays for the Chicago Bears. They have three children together.