A high-speed chase ensued with officers from Lehi, Draper, and the Utah County Sheriff's Office all in pursuit. In Salt Lake County, UHP troopers set down road spikes near 4500 South on the highway, puncturing the left-side tires of Knight's truck.
With officers in pursuit, Knight continued to drive, but slower, riding only on the rims of his left wheels from about 2600 North in Woods Cross, Baird said.
Davis County sheriff's deputies also joined the chase and deployed an armored car used by its SWAT team, which pulled a PIT maneuver near 200 North between Kaysville and Layton that forced the suspect's truck to stop, Baird said.
Knight got out of his pickup holding a handgun and exchanged heated words with officers, Baird said. When he raised his gun and pointed it at police, they opened fire, injuring him.
Knight died at the scene despite receiving medical attention, Baird said. No one else was injured.
Four officers fired their service weapons, three from Davis County and one from another agency, which Baird could not identify.
It was not immediately clear whether the suspect ever fired his weapon, he said.
"These officers did everything they could to compel this man to comply," Baird said. "[Officers] yelled commands at him, and he would not drop his weapon and when he pointed a gun at them, they took the actions necessary."
All four officers were placed on administrative leave pending an investigation of the shooting.
The shooting and the subsequent investigation of the crime scene shut down I-15 between Park Lane Road, just north of Farmington, and Hill Field Road until about 11:15 p.m.
By some accounts it took northbound drivers more than two hours to get just from Salt Lake City to the Farmington area. Some drivers tried to use emergency lanes and shoulders.
Congestion on I-15 also contributed to a fatal collision caused when the driver of a Subaru Legacy failed to safely slow down when approaching slowed traffic, the Utah Highway Patrol said. The Suburu veered left to an emergency lane about 8:30 p.m. and then overcorrected to the right and hit another car. The Subaru then hit the back end of a semi-trailer and as it slid further right, its driver was ejected from the vehicle.