GOLETA, Calif. — Thousands mourned the deaths of their classmates at a California university, lawmakers proposed ways to prevent the next round of deaths, and the rampant presence of guns were at the forefront of both discussions as a rampage that left seven dead reverberated across the state.

Richard Martinez, whose son, Christopher Michaels-Martinez, 20, died in the attacks, spoke at Tuesday’s memorial on the campus of the University of California, Santa Barbara, emphasizing that he did not speak for all the victims’ relatives or even his former wife, Michaels-Martinez’s mother.

But he urged students to fight for tougher gun laws, and placed the blame on what he called the inaction of politicians.

“They have done nothing, and that’s why Chris died,” Martinez said. “It’s almost become a normal thing for us to accept this.”

He got much of the crowd to repeatedly chant “Not one more,” in reference to such massacres, a phrase he shouted before reporters and television cameras the day after Friday’s massacre.

The school canceled classes and declared a day of mourning and reflection, four days after the shootings and stabbings in the Isla Vista community by 22-year-old community college student Elliot Rodger, who had posted an Internet video outlining his plan to slaughter as many people as possible.

Rodger had legally obtained three semi-automatic handguns and still had 400 unspent rounds of ammunition when he shot himself to death, authorities said.