The family of a single mother shot dead in a double homicide at a B.C. sushi restaurant this weekend is struggling to understand why it happened.

Chinh Diem Huynh, 34, was killed Sunday night alongside 36-year-old Huong (Andy) Tran at Royal Oak Sushi House in Burnaby. Police say neither victim was known to police and have described it as a "cold and callous" killing.

Huynh was a waitress at the sushi restaurant, according to her family. Her mother told CTV News through a translator that she panicked when her daughter didn't call after her shift was over.

"She was waiting and waiting until 10:30. She was really nervous and worried. She kept calling and calling and calling and no one picked up the phone," the translator said.

Those who knew her described Huynh as a kind woman who was always joking and smiling. She was raising a four-year-old daughter on her own.

"The daughter is very smart and she continues asking, ‘Where's my mom?'" the translator said.

Police believe the double slaying could be connected to Angus David Mitchell, the man shot dead by police in Maple Ridge a day after he allegedly opened fire on his former landlord. Investigators haven't revealed why Mitchell is considered a person of interest, but a source has told CTV News that he or his van may have been spotted at the sushi restaurant on the night of the shooting.

CTV News has also learned that Mitchell was fired from his security job in October, the same month he was evicted by his landlord, who was seriously injured in this week's shooting. Mitchell attended high school in Vernon and has also worked for security companies in Victoria.

With a report from CTV British Columbia's Scott Roberts