EDMONTON, Alberta >> Police were searching Friday for a security company employee charged with murder in the attempted robbery of an armored truck at a western Canada university that left three armed guards dead, police said.

Police said Travis Baumgartner, a 21-year-old employee of G4S Cash Services, was wanted on three counts of first-degree murder and attempted murder for critically injuring a fourth employee. Canadian authorities said U.S border officials had been notified as well.  

Baumgartner’s mother issued a statement pleading for her son to surrender and apologizing for an argument they had.

The armored truck was found abandoned but running not far from the security company’s offices. Police believe Baumgartner was working alongside his co-workers when they were shot.

“We now believe this is the person that is responsible for this horrific and terrible crime,” Police Supt. Bob Hassel said.

Police said no University of Alberta students were involved. The university was quickly put on lockdown, but that was later lifted.

G4S Cash Services spokeswoman Robin Steinberg confirmed that two male employees and a female employee were among the dead. She said the guards were armed, but she did not have further details.

Steinberg said the company, which operates in more than 100 countries, had never had a fatality in Canada.  “It’s horrible to lose this many,” she said.

Friday’s shooting happened shortly after midnight in the Hub Mall area, which has student residences and shops. It’s the university’s summer session, so fewer students are living on campus. Police had already said Baumgartner was on a crew from G4S Security that was restocking a bank machine at the mall overnight.

“At some point during the delivery, three of those employees were shot,” Edmonton police chief Rod Knecht said during a news conference. “A fourth employee was shot outside the mall.”

Henrietta Shegelski said her daughter-in-law Michelle Shegelski , 26, was among those killed. She said Michelle worked for the company for years and had recently married.

Police later identified the other two dead as Eddie Rejano, 39, and Brian Ilesic, 35.

Such shootings are rare in Canada, where residents are nervous about anything that might indicate they are moving closer to U.S. levels of gun violence. The oil boom town of Fort McMurray, Alberta, however, often has drug-related shootings, and Vancouver often has gang shootings. Gunfire at Toronto’s most prominent mall this month left two dead and several injured. A shooting at an Edmonton club in 2006 left three dead.

It was the second robbery of a G4S armored vehicle in Edmonton in recent months. Last December, guards making a mid-afternoon pickup outside a casino were attacked and pepper-sprayed by two masked men. The pair fled in a Jeep with an undisclosed amount of money. Police have not made arrests in that case.

Ian Breitzke, a student, said he was watching TV when he heard a man crying out in pain. He said when police came about 10 minutes later they broke down the door to a room behind an ATM machine and pulled out two people who seemed dead.

The student said police then pulled out a man who was alive.

One photo posted to Facebook was taken from a balcony looking down into the mall. It shows three people lying in front of a TD bank machine, with emergency crews working over them. Blood streaks the floor from behind the machine to where the bodies are.

“The university is saddened about those who lost their lives last night and we extend our condolences to their loved ones,” the university said on its website.

It said the rest of the campus was operating as normal.

Baumgartner was believed to be driving a Ford F-150 truck with an Alberta license plate that he recently changed to CAA 636, authorities said.

Steven Munz, a close friend of Baumgartner, said earlier Baumgartner had been on the job for only three months and wanted to eventually become a police officer.

“But he felt he really didn’t have what it took,” Munz said.

Munz said he’s surprised Baumgartner could be involved, but had noticed his personality change in the last year.

“Over the last year I’ve kind of noticed him slowly changing as a person. It’s almost more irrational the way he thinks,” he said. “I didn’t think he was capable of something like this, but who knows, right?”

In a profile on the dating website Plenty of Fish, Baumgartner bills himself as an armored car guard who is into video gaming. A photo shows him shirtless holding a cell phone. He says he has a laid back personality and a “10” physique.

“I’m a great guy. We don’t come around often,” he writes.

Munz said Baumgartner lives with his mother and step-sister in Sherwood Park, a bedroom community just east of Edmonton. Police patrolled the area.

“Trav’, as your mother, I ask that you come forward now and take responsibility for your actions,” his mother Sandy said in the statement. “Please Travis, I love you, and I’m pleading with you with all of my heart, to end this without further bloodshed. As your mother, I promise to you now, that I will be there by your side to support you.”