(CNN) -- Sorority sisters.
Roommates and a visiting friend.
A college student shopping at a deli.
These are the six people Elliot Rodger killed in a rampage Friday night near the University of California, Santa Barbara, police said. The violence came to an end when Rodger died, apparently from a self-inflicted gunshot wound, authorities said.
By Monday, the names of all of Rodger's victims had been made public. There has been a call across social media to keep their names in the headlines as much as his, to remember and honor them while interest continues in what might have motivated their killer.
The violence began, police said, when Rodger attacked three men who were in his apartment. Cheng Yuan Hong, 20, George Chen, 19, and Weihan Wang, 20, were found stabbed in the home, officials said.
Hong and Chen are listed on the lease with Rodger. A law enforcement source said the third victim in the apartment was a visitor, adding that authorities are working on a theory that the attack happened as the men slept.
Katherine Cooper, 22, and Veronika Weiss, 19, were later killed outside a sorority, and Christopher Martinez, 20, was killed at a deli, officials said. They were students at UCSB, the school's Chancellor Henry T. Yang said in an online note about the tragedy Sunday.
Martinez's father gave a wrenching statement to the news media Saturday afternoon. His son was "a really great kid" whose "death has left our family lost and broken," Richard Martinez said.
"Our family has a message for every parent out there: You don't think it will happen to your child until it does," the visibly emotional parent said, his voice rising to a shout in obvious agony.
"Why did Chris die? Chris died because of craven, irresponsible politicians and the (National Rifle Association). They talk about gun rights -- what about Chris' right to live?" he continued. "When will this insanity stop? When will enough people say stop this madness, we don't have to live like this? Too many have died. We should say to ourselves -- not one more."
The comment touched a nerve among many Americans, and it prompted the president of the Brady Campaign to Prevent Gun Violence to say the grieving father "got it exactly right."
"It is time for the American public to know the truth about why people are dying every day and, thanks to Americans like Mr. Martinez, that truth is starting to be heard," Dan Gross said in a statement Sunday.
Jeff Dolphin, Christopher Martinez's former roommate, remembered how his friend had always been there for him, the Los Angeles Times reported.
A second-year student at UCSB, Dolphin recalled living with Martinez during their freshman year, the newspaper said.
"Chris was just an amazing guy," he told the Times. "If I was going through something, he was always there for me. If I needed something, he was there. If I needed a textbook, if I was locked out of the room because I forgot my key, he would stop playing basketball or doing what he was doing to unlock the door so I didn't have to get charged. He was just a great guy."
Lyssa Hopper, a 19-year-old student, was at the counter of the I.V. Deli Mart, Hopper told the newspaper. When shooting began, Hopper dropped to the floor, looked up and saw Martinez lying near the door.
"He was slumped over, and he was bleeding," Hopper told the newspaper.
There were 13 others who were injured, police said. Four were hit by a vehicle, eight were shot and one was being treated for injuries whose cause was unclear, authorities said.
On Monday, three patients remained at the Santa Barbara Cottage Hospital, spokeswoman Maria Zate told CNN. Two patients were in good condition and one was in fair condition, she said.
On Sunday at the deli, flowers and cards dotted the sidewalk. One message, with a large red heart, read, "We will miss you, Chris."
Flowers were wedged into holes left by bullets in the glass storefront.
'What a tragic loss'
On Sunday, Tri Delta sorority tweeted about Cooper's and Weiss' killings.
"Tri Delta is saddened by the tragic loss of two members at UCSB. Our thoughts are with their family, friends, and Gamma Theta Chapter," it read.
Weiss' Facebook page -- with a banner promoting a sorority event -- was filling with tributes Saturday evening.
"Rest in peace Veronika Weiss. Its not fair that life was taken from you in this manor. My thoughts are with your loved ones," wrote one commenter.
"... You were ALWAYS smiling. And I thought you were beautiful. Where are you now?" wrote another.
"My condolences to the family... What a tragic loss... R.I.P.," read a third.
Weiss was a graduate of Westlake High School in Thousand Oaks, California, according to her Facebook page. She was a water polo athlete, according to USA Water Polo, which tweeted that the organization was mourning the loss of its former member.
Katie Cooper was with Weiss near the Alpha Phi house when the two were killed, reported CNN affiliate KTLA. Cooper studied art history and archaeology at UCSB, according to her Facebook page, KTLA said, and graduated from Ruben S. Ayala High School in Chino Hills in 2010.
In an interview with CNN, Bob Weiss, Veronika's father, described his daughter as "kind" and the sort of person who would "reach out" to those who weren't popular or who were "nerdy." He said those descriptions were not unlike the way shooter Elliot Rodger portrayed himself -- as being "a little bit of an outcast."
"He had no idea who he was killing," Weiss said. "If he was able to communicate to Veronika, she would have reached out to him. She would have tried to help him. And she would have tried to be friends to him."
Shooter's YouTube video titled 'Retribution'
In a YouTube video he posted titled "Retribution," Rodger announced his intent to commit mass murder at a sorority house at UCSB.
"On the day of retribution I'm going to enter the hottest sorority house of UCSB," he said. "I'll take great pleasure in slaughtering all of you."
Nick Pasichuke, who was hit by Rodger's BMW, suffered two broken legs.
"There was a guy driving a BMW. I was on a longboard (elongated skateboard) and he aimed his car at our group of friends and gunned it into us," he said. "I have two broken legs and need surgery. The police said I flew roughly 50 feet into a busy intersection."
He added, "This is all so crazy."
Witness: 'She was hysterical'
Skylar Serge witnessed one of the shootings from her house.
"I could see a woman on a bike get thrown," she said. The woman was bleeding, she added.
"She was hysterical. She was not sure if it was blood running down her leg" or water from her water bottle.
The woman was cared for by an employee from a nearby convenience store who wrapped a belt around her thigh to stop the bleeding, said another witness, Farah Reiz.
The shootings occurred in a crowded area bustling with activity on Memorial Day weekend.
"These students are among the best in the country, and the loss of life is palpable," University of California system President Janet Napolitano told CNN.
President Barack Obama and first lady Michelle Obama were sending prayers to the families and friends of the victims. A homeland security official briefed the President about the shooting on Saturday.
A posting about the rampage appeared on UC Santa Barbara's website.
"We are horrified and deeply saddened," it read, confirming that students had been taken to hospitals. The posting promised that the university would share more information as it became available and said that counselors are being made available.
The flag on the campus will fly at half-staff, it said, to honor those who lost their lives.
CNN's Sara Sidner, Evan Perez and Jim Acosta contributed to this report.