Thousands of students, faculty and other mourners have gathered at a university in California to remember the six young people killed and 13 wounded in a rampage on Friday night.
The father of one of the dead called for stricter gun control, saying, "life doesn't have to be like this".
The vigil was held at the University of California, Santa Barbara.
The man named by police as the killer, Elliot Rodger, 22, took his own life. He had warned of the rampage online.
'Not one more'
Richard Martinez, whose son Christopher Michaels-Martinez was among those shot dead, addressed the thousands of mostly young people sitting in the sun in the university stadium on Tuesday.
He called for the students to turn their grief into action.
"Not one more,'' he said.
"It's intolerable. We all know it. We know what's happening here and it's unbelievable that we're at this point. Too many people have died, and it should be not one more. They [politicians] have done nothing and that's why Chris died... in my opinion."
"It's almost become a normal thing for us to accept this,'' he said, referring to mass-killings. "It's not normal... life doesn't have to be like this."
Janet Napolitano, president of the University of California system and former homeland security secretary under President Barack Obama, said the campus would recover.
"As long as we hold them in our hearts, they are not gone,'' she said.
"We grieve together as a community of the University of California, and we will get through this together.''
'Hatred be gone'
Mr Martinez also read statements the families of other victims.
"May we together create a peaceful world and let hatred be gone with the wind," the Hong family statement said.
Rodger, a student at nearby Santa Barbara City College, legally purchased ammunition and three handguns. On Friday evening in his apartment he stabbed to death his two room-mates George Chen, 19, and Cheng Hong, 20, and a third man Weihan Wang, 20.
He then got into his BMW and went on a rampage through Isla Vista, shooting at random and killing Katherine Cooper, 22, Veronika Weiss, 19, and Martinez, 20.
Rodger had warned of his intentions in his emailed manifesto and a YouTube video posted the day before, in which he ranted hatefully about women, especially those who had spurned his romantic advances.
His parents reportedly received a copy of the manifesto, called the police and raced to Isla Vista, a beachside university town, to stop him but were too late.