The theft of a commercial jetliner in St. George, Utah early Tuesday by a rogue pilot is unprecedented in modern aviation history, said an industry consultant and two airline pilots.

Under the cover of darkness, a SkyWest pilot, suspected of murdering a former girlfriend in Colorado Springs last week, sneaked aboard the empty 50-seat Canadair Regional Jet 200 just before 1 a.m. Tuesday, started its engines, scraped the terminal building with the left wing, then crashed into several vehicles in the airport parking lot before coming to a stop, authorities said. The pilot, Brian Joseph Hedglin, then committed suicide.

“I’ve never heard of it, ever,” said Mike Boyd, an aviation consultant in Colorado, on Wednesday. “Not a lot of people know how to fly. This is unprecedented because it was a pilot. It wasn’t a random act. It was a pilot who wanted to steal an airplane.”

In separate interviews, the two airline pilots — who were not authorized to identify themselves because of the sensitivity of the case — said they had never heard of a similar occurrence in the U.S. There have been thefts of smaller, personal aircraft, they added, but to their knowledge nobody had ever managed to steal a passenger jet.

“Psychological screening on pilots is so thorough that it’s unlikely that you’d have this sort of thing,” one of the pilots said.

Details of how Hedglin pulled off the unusual heist were still incomplete Wednesday.

Marissa Snow, a spokeswoman for St. George-based SkyWest, said Hedglin was placed on administrative leave Friday after the airline was contacted by Colorado Springs police about the slaying.

Colorado Springs police said they quickly identified Hedglin as their suspect and went so far as to contact SkyWest and have them deactivate the man’s access cards in the event he showed up at a company facility.

Police spokeswoman Barbara Miller said Wednesday that investigators found that Hedglin worked part of the time for SkyWest in St. George and had family in the area.

Snow declined to say whether Hedglin was familiar with the new St. George Municipal Airport, which opened in January 2011, adding that she could not discuss his employment because it was a personnel matter. Snow said that Hedglin’s access cards were deactivated.

Shortly after midnight on Monday, authorities said, Hedglin drove a motorcycle up to a security fence. He donned a pair of leather gloves and threw a blanket over the razor-wire fence before climbing over it.

The pilots speculated that once inside the secure area, Hedglin either gained access to a jetway connecting the plane to the terminal building or he ascended a flight of steps from the tarmac to the aircraft’s door.

But Marc Mortensen, St. George city spokesman, said the jet has multiple entrances, and “We don’t know what door he went in.” Mortensen said Hedglin would not have been able to access the jetway from the tarmac.

Both pilots said aircraft doors are latched but typically aren’t locked from the outside because first-responders need to gain access to a plane’s cabin quickly in the event of an accident. Once inside, Hedglin would have entered the cockpit through a door that locks only from the inside. At the controls, a trained commercial pilot would have no difficulty starting the plane’s engines, they said.

“Stealing an airplane [actually] is easy. Once you get into the airplane, there’s no key required” to start the engines, one of the pilots said.

That’s news to Mortensen.

“The city did not know that was possible … for someone to walk up to an aircraft without a key or something to unlock a door,” Mortensen said. “I’m sure most of America didn’t know that until yesterday.”

Snow would not discuss how Hedglin might have gotten aboard the jet or how security procedures might change in the aftermath of the incident.

“We are assisting the investigation on that. What I can tell you is it takes a sophisticated procedure to access and start the aircraft,” she said.

Hedglin probably activated the plane’s auxiliary power unit, or APU, which provides electricity and air to the aircraft until the engines are running, the pilots said. To start the passenger jet’s two engines, Hedglin would have diverted the air from the APU to the engines’ turbines. He also would have applied fuel and electricity.

Both pilots said it is unlikely that the jet was fully fueled, and Hedglin would have known that. Fueling usually takes place shortly before an aircraft starts its day, they said.

“Usually they are fueled before they go,” one pilot said, who speculated that Hedglin probably wasn’t trying to flee the country.

“I think it was just one last hurrah,” the pilot said.

The pilots said it’s unlikely that someone could steal a commercial aircraft at Salt Lake City International Airport, which is much larger and busier. People are around jets at the airport constantly, they said.

By contrast, the St. George airport is lightly guarded and closed at night. From 10 p.m. to 6 a.m., one St. George police officer patrols the six-mile perimeter. Early Monday, the officer noticed something was awry when he found the motorcycle parked near the southeast fence, the engine still warm.

Mortensen said the perimeter is “100 percent compliant with federal security protocol,” but he added that airport officials plan to fully re-evaluate all security protocols, working with SkyWest, the National Transportation Safety Board, the Federal Aviation Administration and the Transportation Security Administration, which regulates security plans for each airport.

Aviation consultant Boyd, who knows SkyWest well, believes Hedglin was familiar with the St. George airport. Most of the airline’s pilots come to SkyWest’s headquarters to train on simulators, he said.

“He was familiar with the airport, familiar with the airplane, so he tried to steal it,” Boyd said.

SkyWest employees painted over the airline logo on the plane soon after detectives finished gathering evidence from the aircraft Tuesday. Snow on Wednesday said it was an industry practice to paint over the logos on aircraft that have been involved in any sort of incident.

In Colorado Springs, police continue to investigate the murder of 39-year-old Christina Cornejo, who was stabbed to death. Police clarified that they found her body in Hedglin’s home despite a restraining order and charges against Hedglin stemming from domestic-violence allegations in March.

Investigators do not know why Cornejo was at Hedglin’s house, police spokeswoman Miller said. Although investigators have no suspects other than Hedglin, they are processing all evidence before closing the case, Miller said. She would not comment on whether further evidence was gathered from Hedglin’s motorcycle or body in St. George.

Cimaron Neugebauer contributed to this story.