Mystery as Kristin Cavallari's brother goes missing

A 2014 Honda Civic registered to Michael Cavallari, of San Clemente, Calif., was found abandoned in Grand County, Utah, on Nov. 27.

Kristin Cavallari and her family, including husbandJay Cutler of the Chicago Bears, were hoping for good news Monday about her brother Michael Cavallari, who's been missing in Utah for more than a week.

She tweeted thanks for messages of support Monday.

A 2014 Honda Civic registered to Michael Cavallari, of San Clemente, Calif., was found abandoned in Grand County, Utah, on Nov. 27, about 100 feet from a road, according to a statement from the county sheriff's office.

Grand County is about 225 miles south of Salt Lake City.

Sheriff Steven White told local reporters that it appeared the car had hit a large rock on the side of the road. He also said there were no signs of foul play.

His office provided the media with a dramatic photo of tire tracks leading off the road to the back of a car alone in the desert scrub landscape.

The car was still running and the airbag had deployed. The sheriff said the driver could not be found nearby and was identified as Michael Cavallari from credit card receipts found inside, along with a laptop and cellphone.

The receipts led 100 miles away to a convenience store in Monticello, Utah, where they saw Cavallari in footage on the store's security system, the last time anyone has seen him.

"We're combing the area for anything we can find," White told TV station KSL said. "We're deeming it suspicious, but there's nothing to indicate anything one way or another. The vehicle was just abandoned."

Michael Cavallari is the brother of Kristin Cavallari, a reality TV star (MTV's Laguna Beach and The Hills) , and wife of Bears quarterback Cutler.

Kristin Cavallari and her husband last month welcomed their third child, a girl, Saylor James Cutler. The couple also have two young sons.

Contributing: The Associated Press