EDMONTON -- An armoured car worker who is the subject of a Canada-wide manhunt has been charged with three counts of first-degree murder and one count of attempted murder.

Investigators are asking anyone with information about Travis Brandon Baumgartner, 21, to contact police and not to approach the man deemed armed and dangerous.

Police across the country are searching for Baumgartner after three of his coworkers were shot dead and a fourth left clinging to life during a heist at the the University of Alberta just after midnight Friday.

He is the owner of a dark blue Ford F-150 pick-up truck with Alberta licence plate number, ZRE 724.

The three G4S Security guards -- two men and a woman -- were killed during an exchange of funds inside the HUB Mall.

A fourth victim, a man in his 20s, was taken to hospital in critical condition. He was undergoing surgery for a gunshot wound to the head, says a source who is close to the man's family. The victim has a fiance and a young child.

"To lose one employee would be devastating. To lose three employees is beyond heart wrenching," said company spokesman Robin Steinberg, manager of marketing and communications, G4S Cash Services,
At 8:32 a.m. Friday, investigators and the medical examiner removed one body from the scene. The two remaining bodies were taken from the scene just before 12:30 p.m. Friday.

A black tarp had been set up underneath the mall's pedway and forensic investigators worked behind it. That is where one of the victims -- a man -- was shot dead. The other two victims -- a man and woman -- were removed from the bank machine vault.

The surviving man was earlier taken from the vault after police used a battering ram to bust down the door.

Later Friday morning, officers surrounded a second armoured car discovered outside the Edmonton Sun press plant.

Investigators have determined the second armoured car is empty and was abandoned.

They believe it may be a getaway vehicle.

Edmonton Sun surveillance video from the press plant -- adjacent to the G4S Security armoured car parking lot -- shows the second armoured car park at the lot where the driver exits sometime before 1 a.m. He gets into an awaiting truck which then drives away.

City police have reached out to counterparts across the country as they search for the killer or killers.

They believe the robbery was an inside job perpetrated by persons who knew the armoured cars' routes.

Baumgartner's home was surrounded by RCMP and city police Friday afternoon though it was not believed he was inside.

"To the families of those involved, and to the co-workers of these employees from G4S, all of us here at the Edmonton Police Service, and all the citizens of Edmonton, share your feelings of shock and disbelief," Police Chief Rod Knecht said. "Our thoughts are with you at this difficult time."

No students were harmed or involved in the shooting.

While armoured car robberies are rare across the country, Edmonton had a previous heist in December. On Dec. 1, a daring daylight robbery of an armoured car occurred outside the Century Casino in north Edmonton.

That case remains unsolved. Police said a man dressed in black pepper-sprayed an armed G4S Security Services guard outside the casino at about 1:55 p.m. Dec. 1 before grabbing cash.

At the time, Det. Ron Gamble, with the city police robbery section, said "this city is a violent place to live in and it's getting more violent. ... Any time an offence like this happens, it's violent and it puts people at risk."

G4S Security Systems is one of the biggest security companies in the world.

G4S guards in Canada carry firearms.

One of Edmonton's most memorable armoured car heists occurred in 1999 outside Palace Casino at West

Edmonton Mall.

Charges were laid after investigators tracked the suspect to a Montreal jail where he was serving a 32-year sentence for various robberies and other criminal offences.