The University of Utah student shot and killed Monday at the mouth of Red Butte Canyon was not alone in the car that night, police said Wednesday.

A female friend of ChenWei Guo’s was in the car with the man when 24-year-old Austin Jeffrey Boutain allegedly shot and killed him, University Police Chief Dale Brophy said. The woman, also a student at the U., requested that police not identify her publicly.

The woman told police that Boutain tried to force her up into the canyon. When he was distracted, she ran away, and then he allegedly fired at her, according to a statement from campus police.

Brophy didn’t release a possible motive for taking the woman into the foothills, other than saying Boutain had “ill-intent.”

The woman was uninjured, though “very traumatized,” and had a difficult time describing what happened to investigators “due to the amount of shock she was in,” Brophy said.

After the shooting, police believe Boutain crawled north up in the foothills and made his way to the Avenues area. From there, he walked into downtown and was arrested just before 1 p.m. Tuesday at the Salt Lake City library, Brophy said.

In an interview with Boutain, the man admitted to killing 23-year-old Guo to steal his vehicle, police documents say.

Boutain told officers he also fired two rounds at the woman as she ran away from him “with the intent to kill her so there were no witnesses,” documents say.

ChenWei Guo (Photo courtesy University of Utah)

The woman’s story gave officers “very limited details,” Brophy said, but they unraveled more about Monday night’s events when they arrived at the scene and when they interviewed Boutain the next day.

Boutain, of Mississippi, was booked into the Salt Lake County jail Tuesday night after answering questions from police and leading them to a campsite where he’d stayed over the weekend with his wife, 23-year-old Kathleen Boutain.

He is being held on suspicion of aggravated murder, along with several other potential charges. Formal charges have not been filed.

Meanwhile, Golden, Colo., police on Wednesday named the Boutains as the sole suspects in the recent slaying of a man there.

In his interview with U. police, Boutain admitted to stealing three guns from a home in Colorado. Police recovered one those guns — a rifle — when they were searching the foothills for Boutain, documents say. Boutain told police he traded a second firearm, a .38 caliber Smith and Wesson, for an ounce of marijuana.

He hid the third weapon, a .44-caliber Ruger believed to have been used to kill Guo, in a crevice of a brick wall near the Salt Lake City homeless shelter, Boutain said. He told police that when he returned to retrieve the weapon, it wasn’t there.

As of Wednesday evening, police had not found the Ruger, which is believed to have been stolen from the Colorado homicide victim.

When Boutain led police to a makeshift camp in Red Butte Canyon above the university, detectives found the holster for the Ruger, as well as six spent .44-caliber cartridges.

Police have not released the number of times Guo was shot. Brophy said Wednesday that the medical examiner was still compiling his report of the autopsy.

Guo was an international student from China at the U. The university canceled classes Tuesday in light of the tragedy and lowered flags to half-staff Wednesday in Guo’s memory. Spokesman Chris Nelson said the flags would remain at half-staff until sunset Friday.

Boutain is also accused of assaulting and injuring his wife, Kathleen Boutain, with a firearm in the canyon, documents say. Campus police described the alleged assault as the first in a series of events that led to Guo’s death.

On Monday night about 8:15 p.m., Kathleen Boutain reported the assault to U. police. As police were taking the report on the domestic violence incident, they learned that Guo had been shot and killed.

During her interview with police, Kathleen Boutain told police she and Austin Boutain had traveled to Utah in a stolen vehicle with stolen firearms, documents say.

Campus police characterized the couple as “drifters,” who chose to come to Salt Lake City because it‘s close to Colorado and because they were familiar with the area.

They had been in town — mostly staying near downtown shelters — since Oct. 28, according to a statement from campus police.

(Photo courtesy of Salt Lake County Sheriff's Office) Kathleen Boutain

Kathleen Boutain, of Alabama, was booked Monday night into the Salt Lake County jail, where she was being held in lieu of $25,000 on suspicion of theft by receiving stolen property and drug possession charges. Police said she had a prescription bottle of generic Ambien, which was not labeled, and other drug paraphernalia.

Police investigators from Golden, Colo., spent Tuesday and Wednesday in Salt Lake City interviewing the Boutains in connection with the slaying last week of 63-year-old Mitchell Bradford Ingle.

On Tuesday, police found Ingle dead inside an RV trailer at a Golden RV park after Utah authorities contacted them in connection with the university shooting. The Boutains apparently killed Ingle and then drove his pickup truck to Utah.

A preliminary investigation indicated Ingle had been dead a few days before police found him, the Golden police department said in a news release.

Ingle’s body had obvious signs of trauma, Golden police said, and a coroner has ruled his death a homicide, the release said. Other details about his death were not immediately released.

“The victim and the suspects just recently met and did not have a long-term relationship,” the release said.

(Photo courtesy of Golden Police Department) Mitchell Bradford Ingle was found deceased in his RV trailer on Monday.

Investigators plan to recommend the Colorado prosecutors file charges including first-degree murder, robbery and motor vehicle theft, the release says.

In Utah, police said Wednesday they had been unable to locate the stolen vehicle, described as a green 2000 Ford pickup truck with Colorado plates.

The Boutains apparently gave the truck to another transient couple when they arrived in Salt Lake City, Brophy said Wednesday.

News outlets in Alabama and Ohio report that Austin Boutain’s criminal history includes charges involving public disturbances, theft, evading police, drug-related charges and a sex offense.