A 19-year-old man from Ottawa has been identified as one of the victims of Friday's mass murder at the University of California at Santa Barbara.

George Chen, who was studying computer science, was a graduate from Leland High School in San Jose, Calif., and one of six people killed.

Family friend Sherry Shih told the San Francisco Chronicle that Chen was a gentle soul who had a fondness for working with children.

George Chen, 19, was stabbed to death, along with two others, in Elliot Rodger's apartment before Rodger went on a shooting rampage. (Facebook) Shih said Chen was a "very good kid, very smart," and that his parents are in a "very, very sad mood" and unable to speak about what happened.

Chen's parents visited a makeshift memorial on Monday night and added their names in chalk to the sidewalk.

They told KABC-TV that the United States needs tougher gun laws to avert another mass killing.

A note addressed to George Chen, one of three men found stabbed to death in the apartment of Elliott Rodger, is seen outside the apartment where he lived in the Isla Vista neighbourhood of Goleta, Calif. (Christopher Weber/AP) "We would die a hundred times, a thousand times, but we don't want our kids to get hurt," Chen's mother, Kelly Wang, said as she spoke through tears.

"This shouldn't happen to any family."

The man identified as the killer, Elliot Rodger, died of an apparent self-inflicted gunshot wound to the head after a shootout with police.

Before the rampage, Rodger left a trail of YouTube videos ranting against women and complaining that he was a lonely and frustrated virgin.

Campus in mourning

Meanwhile Tuesday, students at the University of California at Santa Barbara returned to campus for a "day of mourning."

All of my friends are very strongly affected by this - William Tobolowsky, UCSB student

The university cancelled classes, but faculty were asked to be on hand to meet with distraught students during a memorial at Harder Stadium.

A memorial service for the six students who were slain on Friday night was scheduled for afternoon and eight large blackboards were erected on a street corner in the community of Isla Vista, near the campus, where students were encouraged to write messages in chalk.

Students stopped by to leave flowers and candles at makeshift memorials at the shooting scenes. Some placed flowers through bullet holes in the windows of a store.

"All of my friends are very strongly affected by this," said William Tobolowsky, a 20-year-old microbiology major at UCSB.

"Isla Vista is a close-knit community where everyone knows everyone to a certain extent."

"It's important that everyone has the opportunity to be sad and upset," he said. "It's important to have a day dedicated to it so we have time to reflect."

University of California President Janet Napolitano has ordered flags at all 10 UC campuses lowered to half-mast to honour the victims.

All six people killed — two women and four men — were between the ages of 19 and 22 and were students at the UCSB. Another 13 people were wounded, including eight who were shot by Rodger as he sped through town in his black BMW, exchanging gunfire with police.