NEW YORK -- In the early morning hours of Nov. 27, Michael Cavallari stopped for gas in Monticello, Utah, went inside the station's convenience store, and then proceeded north on Interstate-70 toward Salt Lake City.
But about 90 miles away, the brother of television personality Kristin Cavallari left the highway at barren Exit 175, driving along a dirt track called Floy Wash Road for about five miles. He veered off the road and his car soon plunged into an embankment.
Cavallari got out of the car and likely wandered into the rocky, frigid desert. Daylight would reveal tire marks leading back from his Honda Civic to the road. It's not clear when he left the car, but he didn't follow the car's path back.
Temperatures in the Salt Wash, the steep, boulder-specked area where Cavallari was found, rarely rose above the 30-degree range in the week he went missing, said Grand County Sheriff Steven White, in an interview Friday with 48 Hours' Crimesider.
"In the area he was in it was very rough," White said, noting that as many as 30 deputies combed the area, along with dogs and drones. "It made the search very challenging."
Cavallari was found wearing the same clothes he had on when he stopped at the gas station in Monticello. A thin, long sleeve green shirt, jeans and sneakers. The terrain is difficult to navigate, even for experienced locals, according to White.
Grand County, Utah, Sheriff's Office video of the area in Utah where authorities searched for Michael Cavallari
"I actually have the busiest search and rescue team in the state," White said. "A lot of the rock formations look the same, so it's easy to get lost out there."
If Cavallari left his car hoping to find the highway, five miles north, he went in the wrong direction, according to police. It would have been a trying hike even for those well prepared for the elements, White said.
His body was found between two and three miles southwest of where he crashed, police said. His family was notified of his death Thursday.
"This is a very painful time and we are still processing it all," Kristin Cavallari told CBS News. "We kindly ask everyone please respect our privacy during our time of grieving."
Michael Cavallari's disappearance and death marked the end of a month-long series of strange incidents, according to police in Dana Point, Calif., about 750 miles west of where Cavallari died.
On Wednesday, Nov. 11, a woman and Cavallari had a verbal dispute, she later told police.
"For several weeks after the incident, Michael kept knocking on her door, but she refused to answer," she said, according to police records.
Then, on Nov. 23, four days before Cavallari disappeared, the woman said she heard tapping on her apartment door from something that "sounded like a piece of metal." She opened the door slightly, saw no one and shut it.
But when she looked out a nearby window, she allegedly "saw Michael with a shotgun pressed to his shoulder and the barrel raised parallel to the ground, aiming down the path" toward her apartment. Cavallari was arrested for criminal threats and spent two days in jail before he was bailed out.
White said Cavallari was in contact with either family or friends during the two days before he disappeared, but it's not clear why he was driving through the night toward Salt Lake City, or why he left the highway and veered into the cold Utah night.
The cause of Cavallari's death has not yet been determined, but White said Cavallari had no visible injuries beyond a few scrapes and scratches.