A 32-year-old woman has been arrested in Minnesota after she was found at the scene of a single-car accident and the body of a dead woman wrapped in a mattress was found in the backseat. 

Authorities responded to the accident in the eastbound lane of Interstate 90 near the Highway 42 exit in Olmsted County — about 100 miles southeast of Minneapolis — on Saturday at 7 a.m., the Olmsted County Sheriff’s Office said in a release Monday.

The driver of the car, Margot Lewis, of North Liberty, Iowa, was found out of the vehicle being tended to by a passerby. 

“In checking to see if anyone else was in the vehicle, a deceased individual, a 35-year-old female, was located in the back seat,” the sheriff’s office said.

The condition of the deceased woman was “suspicious” and “it was immediately apparent that the death was not a result of the motor vehicle accident” the sheriff’s office said. 

The deceased woman was identified Tuesday as Liara Tsai, a 35-year-old woman from Minneapolis.

Lewis was transported to a hospital where she was medically cleared, then transported to the Adult Detention Center and placed under arrest for interference with a dead body. 

According to a probable cause affidavit filed in the case, a deputy found the back seats of the Lewis’ vehicle folded down and found the body wrapped in a bed sheet, blanket, a futon-style mattress and a tarp. The body was cold to the touch and there appeared be dried blood soaked in the bed sheet.

A large wound was also observed the right side of body’s neck. An autopsy found, based on preliminary information, that the fatal injuries to the victim “were not caused by, and preceded, the car crash,” the affidavit said.

The investigation is ongoing. 

Lewis appeared in Olmsted County Court on Tuesday morning and again in the afternoon, where she appears to be representing herself.