The mother of a man wanted in connection to a brazen shooting and robbery at the University of Alberta has issued a statement pleading for her son to surrender. 

Meanwhile, Edmonton police say 21-year-old Travis Brandon Baumgartner may've switched the license plate on his dark blue, Ford F-150. Possible plate numbers include CAA 636 or ZRE 724. He's considered armed and dangerous and anyone who sees Baumgartner is asked to call 9-1-1, rather than approach him.

"Trav, I'm sorry that we had an argument last night and had bad words between us, but I want you to come home and do the right thing." Sandy Baumgartner said in a statement to her son, read by police at news conference Friday night.

Supt. Bob Hassel says warrants have been issued for the arrest of Baumgartner for three counts of first-degree murder and one count of attempted murder.  Baumgartner was on a crew from G4S Security that was restocking a bank machine at the university's HUB Mall just past midnight Friday. He turned the gun on his colleagues then locked them in secure room behind the ATM machines.

Three of the employees — two men and a woman — were shot inside the building during the delivery. The fourth, a man, was shot outside.

The three guards killed in the shooting have been identified as Michelle Shegelski who was newly married, Eddie Rejano, and Brian Ilesic.  One guard remains in critical condition in hospital, he's been identified as Matt Schuman.