The search for Travis Baumgartner intensified Saturday, with Canadian and American border security becoming involved in the hunt for the triple-murder suspect, police said Saturday.

"We have an international manhunt that has been launched," Edmonton police Supt. Bob Hassel said Saturday.

"I can't emphasize enough — and I know I keep saying it and I will continue to keep saying it — we consider him armed and we consider him extremely dangerous.

Police have charged Baumgartner, 21, with three counts of first-degree murder and one count of attempted murder after four guards from G4S Security were shot while refilling an ATM on the University of Alberta campus.

An abandoned armoured car was later found hours after the robbery, halfway across town near a G4S office with its lights on and its motor running.

Baumgartner worked for the same company as the victims. His company-issued firearm and body armour are missing, according to police.

Police said Saturday they believe Baumgartner has switched the licence plate on the Ford truck he is driving. The new plate number is: CAA 636. Police believe the truck has two stickers on it: a Monster Energy drink sticker on the driver's side and a Gears of War logo with a red skull on the rear window.

Wounded guard ID'd Police have identified the guard who survived robbery as Matthew Schuman, a corporal in the Royal Canadian Air Force stationed as a firefighter at Canadian Forces Base Edmonton who held a second job at G4S Security. Late Friday night, Schuman was still fighting for his life in an Edmonton hospital with critical injuries.

Earlier Saturday, tactical teams stormed a chapel inside City Centre Mall in downtown Edmonton following a tip that the suspect had been spotted inside. A man was arrested and released; police called it a false alarm.

Baumgartner's mother made a plea to her son late Friday to turn himself in. She alluded to a fight the two had before the shooting and apologized to her son.

"I'm sorry that we had an argument last night and that we had bad words between us, but I want you to come home and do the right thing. Let's work this out together," she said in a statement read by police.

Police are pleading with friends and family to come forward if they have been contacted by Baumgartner, and are warning all rural residents near Edmonton to call police if they see fresh tire tracks or other signs of the suspect's vehicle.

Michelle Shegelski was one of the G4S employees who was slain early Friday at the University of Alberta. (Facebook)

Friends say Baumgartner had designs on being a police officer, but settled into a job with G4S after deciding he didn't have what it takes for law enforcement. He likes video games and calls himself a recreational drug user. In an online dating profile, he says he is a "great guy" who is laid back and has a "10" physique.

But his Facebook page is much darker, quoting the anarchist Joker from the movie Dark Knight and musing about "popping people off."

Police have also released some details about the people Baumgartner allegedly killed.

Michelle Shegelski, 26, had had recently wed Victor, a former military man who, coincidentally, had just returned to school at the University of Alberta.

"I could never have imagined anything more terrible happening in my life. She is still the embodiment of everything I love and respect, and she is gone. She inspired me to better myself, and brought out the love and emotion I thought I left in the desert," Victor Shegelski wrote on Facebook Saturday afternoon.

"Because of her, I will make this life great and live it for us both. The years we had will never be lost, and the happiness she gave to us all will always be cherished."

Eddie Rejano, 39, and Brian Ilesic, 35, were the other two guards killed.