Kristin Cavallari has thanked her fans for their support as police in Utah investigate the mysterious disappearance of her brother, Michael Cavallari, soon after Thanksgiving.

Michael’s 2014 Honda Civic was discovered abandoned at the side of a highway in Utah on November 27th, according to a press release distributed by the Grand County Sherriff’s Office. An open missing persons investigation is currently being conducted, and authorities are optimistic that he will be found safe and well.

“There's no sign of foul play that we can tell,” Sheriff Steven White of the department told the ‘Today’ show. “We're still piecing everything together.” He indicated that the car had hit a large rock on the side of the road and veered off into scrubland off the I-70 highway, and that the vehicle had come to a stop nearly 100 hundreds later with the airbag deployed.

Michael, a resident of San Clemente, California, was identified as the owner of the vehicle from credit card receipts left inside, plus from a cellphone and laptop.

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Posting a cute throwback picture on Instagram on Monday (December 7th) of her and her brother posing on the beach as children, 28 year old Kristin wrote: “I appreciate all the concern, thoughts, and prayers that have been extended to me and my family. We remain hopeful and I will share any news that we receive. I have such gratitude for all those that have shared their support.”

Just last month, Cavallari and her NFL-playing husband Jay Cutler welcomed their third child, Saylor James, into the world, a sister for their two sons Camden (2) and Jaxon (1).

Anybody with information about his disappearance is urged to contact the Grand County Sherriff’s Office.

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