"He gained unauthorized access to the aircraft," Snow said, but added they don't know how.
Mortensen said a St. George police officer was near the airport just before 1 a.m. doing a regular perimeter fence check when he discovered a motorcycle parked on the southeast side of the airport, the engine still warm.
Mortensen said it appears Hedglin parked the motorcycle, then threw a rug over a razor-wire fence and used leather gloves to scale it. Once inside the fence, Hedglin got inside a regional jet, and started the engine.
Hedglin backed the aircraft away from the jet bridge, Mortensen said, then began to pull forward. The jet's left wing hit the jet bridge, and when Hedglin turned to head east, he scraped the same wing along the terminal building.
Mortensen said the man then drove the jet through a security fence and over some landscaping before finally stopping after hitting multiple cars in the public parking lot.
"At that point in time, the officer was coming up over the hill, and noticed the aircraft in the parking lot," Mortensen said. "He called SkyWest and notified them."
The jet engines were still running when the officer approached the plane, St. George police officials said.
SkyWest officials opened the plane, Mortensen said, and police officers discovered Hedglin had killed himself in the aisle of the passenger area of the plane.
Mortensen said that the whole episode took no more than 10 minutes, according to video footage from airport surveillance cameras. He said an onboard voice recording device may reveal details of what happened while Hedglin was inside the plane.
Colorado Springs police had been searching for Hedglin since 7 a.m. Friday, when they found the body of 39-year-old Christina Cornejo, who had been stabbed to death at Hedglin's home, according to a police news release.
Police said they immediately identified Hedglin the woman's former boyfriend as their suspect. A no-bail warrant for Hedglin's arrest on suspicion of Class 1 felony murder was issued Friday.
On March 10, Hedglin was charged with misdemeanor counts of criminal mischief, harassment and theft, according to El Paso County court records. He pleaded guilty to the harassment charge, but was released on $10,000 bond the next day.
According to the Colorado Springs Gazette, Cornejo told police in March that Hedglin invaded her apartment, took some things he had given to her and smashed a computer. Hedglin and Cornejo had been dating each other for four years when Hedglin was arrested.
Hedglin was scheduled for trial in August. Meanwhile, a judge issued a restraining order prohibiting him from contacting Cornejo, according to the Gazette.
Officers went to Hedglin's home on Friday, following a call from a concerned family member. A coroner ruled the woman's death from "multiple stab wounds" was a homicide, police said.
Colorado Springs detectives contacted SkyWest on Friday and had them deactivate Hedglin's access cards in the event he showed up at a company facility. SkyWest officials also put Hedglin on leave
SkyWest officials confirmed they were cooperating with the FBI's investigation of the incident.
"Today's events are extremely regrettable and we are working closely with authorities and airport officials,"said Snow.
FBI spokeswoman Deborah Bertram said they are assisting St. George police and the Transportation Security Administration, but won't play a large role in the investigation because the suspect is dead.
A news release from the Colorado National Guard confirmed that Hedglin was a Food Service Specialist with the Guard, who had no other specialized training and had not been deployed for combat.
Hedglin probably knew the door code or some other means of accessing the jetway leading to the airplane, said Dave Funk, a retired Northwest Airlines pilot who works as an aviation security consultant for Laird & Associates. Once aboard, Hedglin would know the complicated process required to start the engines.
Funk gave credit to the police officers who realized there was a problem and moved to stop Hedglin.
"Although the [security] system doesn't sound perfect, it worked as it did," Funk said.
Nate Carlisle contributed to this story