Baumgartner, 22, is charged in the June 2012 robbery and fatal shooting of Michelle Shegelski, 26, Eddie Rejano, 39, and Brian Ilesic, 35, at HUB Mall, a student residence and indoor food court. A fourth guard, Matthew Schuman, was critically injured in the shooting but has recovered.
Baumgartner was working as a guard on the same shift. He was arrested days later with $330,000 in cash in his vehicle at a U.S. border crossing adjoining British Columbia.
Last month, Baumgartner's lawyer requested that the trial be switched from jury to judge alone, a request the Crown agreed to.
In reaction to the legal move, Schuman, in an email to CBC News, called Baumgartner's decision not to be tried by a jury "A coward's way out. Just like when he shot us. (From Behind.)"
The time set aside for Baumgartner's trial has also been reduced from three weeks to one after discussions between Crown and defence lawyers.
Baumgartner is charged with three counts of first-degree murder and one count of attempted murder.