Austin Boutain, a suspect in Monday night's fatal shooting of University of Utah student ChenWei Guo, is led out of the University of Utah Department of Public Safety in Salt Lake City, Tuesday, Oct. 31, 2017. Boutain surrendered to police in Salt Lake City on Tuesday after a manhunt in the foothills near the University of Utah campus. Golden police say he's a person of interest in 63-year-old Mitchell Bradford Ingle's death. (Spenser Heaps/The Deseret News via AP)

SALT LAKE CITY - An ex-con accused of killing a University of Utah student from China casually strolled multiple floors of a downtown Salt Lake City library about 15 hours after the fatal shooting and amid a massive manhunt. But he was quickly arrested in a bathroom by security, according to surveillance video released Thursday.

Videos released by the Salt Lake City Public Library showed Austin Boutain, 24, enter the building just after noon Tuesday, about 4 miles (6 kilometres) from the canyon on the edge of the university campus where police believe Boutain killed 23-year-old student ChenWei Guo during an attempted carjacking.

Boutain, with tattoos on his arms, face and back of his neck and wearing a white T-shirt, black beanie and jeans, can be seen carrying a water bottle and dark jacket around as he walks through multiple floors of the library and rides an elevator.

About 20 minutes after he arrived in the library, the video showed Boutain enter a bathroom on the third floor. About two minutes later, a security guard entered the bathroom.

The guard left but returned quickly with a second guard and entered the bathroom with his hand hovering over a gun on his hip.

A third guard can be seen arriving in the hallway, talking on the phone to someone as the other guards emerge from the bathroom with Boutain, whose wrists are handcuffed behind his back.

Police later said he surrendered without incident.

Other library surveillance footage shows Boutain in a library security holding room standing calmly as officers pat him down and have him sit on a bench waiting for police to arrive.

After about 10 minutes, officers showed up and walked Boutain calmly out of the nearly empty library, according to the footage.

Boutain, who has yet been formally charged, was being held Thursday in jail on suspicion of aggravated murder, robbery and other charges. He will likely face charges in Utah, then be extradited to Colorado, where police believe he killed 63-year-old Mitchell Ingle, stole his guns and drove his truck to Utah.

Ingle's body was found in his trailer in Colorado on Tuesday.

Boutain's wife, Kathleen Boutain, is also named as suspect in Ingle's death. She was in jail in Utah on drug and theft charges.

No attorney has been listed for the Boutains.

News from © The Associated Press, 2017