Kristin Cavallari's missing brother asked for directions hours before his abandoned car was discovered in Utah - and was arrested for making criminal threats four days prior

The brother of reality star Kristin Cavallari asked for directions just 60 miles away from where his abandoned car was found in the Utah desert.

Michael Cavallari, 30, has been missing for 10 days and was last seen on November 27 at a convenience store in the town of Monticello where he asked for directions to Salt Lake City.

Surveillance video shows him leaving around 3:30am, just hours before a rancher found his car in Grand County.

Four days before this, on November 23, he had been arrested for making criminal threats - the same day his sister gave birth to her daughter Saylor.

Early reports claimed that Michael was on his way to see Kristin in Chicago when he went missing, but authorities are now saying they are unsure where the 30-year-old was heading.

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Disappeared: Kristin Cavallari's (right) brother Michael (left) has been missing for 10 days and was last seen on November 27 at a store in the town of Monticello, Utah

Seen: He made a purchase with his credit card and asked for directions before he was seen leaving at 3:30am on the store's surveillance camera

Questions: He asked for directions to Salt Lake City and his abandoned car was found hours later in Grand County (above)

Michael made bail two days after his arrest and was released on November 25 by the Orange County Sheriff's Department.

Police have yet to detail the incident that landed him behind bars. 

US Weekly reports that Michael had a previous arrest for a DUI and received three years probation.

Michael's abandoned car was found with its engine on and the air bag deployed near a remote dirt road.

It's unknown why he was driving on a dirt road miles from the main highway. But evidence shows Michael's 2014 Honda Civic hit a couple of big rocks and washes, likely causing the air bag to deploy.

Temperatures in the area have been at freezing or below freezing in the area every night since the car was found, and efforts to locate Michael have not been successful despite crews searching the area on foot and by helicopter.

There were no signs of foul play in or around the abandoned car. 

Behind bars: Four days before his car was found, Michael was arrested for making criminal threats by the Orange County Sheriff's Department (above in a 2013 mugshot for a DUI)

Memories: Kristen shared a childhood photo of herself and Michael on the beach on Monday

Grand County Sheriff Steven White said the young man may have been dealing with some minor issues in his life but nothing major, refusing to elaborate any further. 

He works for his for his father, who has been in Utah along with Michael's stepfather searching for the young man.

His little sister Kristin shot to fame as a teenager with her role on the popular MTV reality show Laguna Beach, and later appeared on the show's even more popular spin-off The Hills.

The 28-year-old briefly tried her hand at acting, has written a lifestyle book Balancing in Heels that will be released next year and designs shoes for Chinese Laundry.

She is also the mother to three children under the age of three - sons Camden and Jaxon and newborn daughter Saylor - with her husband, Chicago bears quarterback Jay Cutler. 

Family: Kristin is the mother of three children under the age of three - sons Camden and Jaxon and newborn daughter Saylor - with her husband, Chicago bears quarterback Jay Cutler (above)

Kristin thanked her fans for their support during this difficult time on Twitter Monday, writing; 'I appreciate the thoughts &prayers that have been extended to me & my family. I have such gratitude for those that have shared their support.'

She also included a childhood photo of herself and Michael on the beach. 

The family asked authorities to respect their privacy in the early days of the investigation but later agreed to go public knowing that Kristin and her husband's celebrity would lead to news coverage and the possibility of individuals coming forward with information.

Police meanwhile are planning to increase their search area in the coming days.