(CNN) -- As a California university mourns the deaths of six students, grieving parents are bracing to do the unimaginable -- bury their children.
A former stay-at-home dad who worked at home, Bob Weiss had an especially close relationship with his 19-year-old daughter, Veronika. He knew something was amiss Friday night when Veronika, who frequently checked in, didn't call her family.
So he tracked Veronika's cell phone online.
"We got on her iPhone and located it in the middle of the crime scene," Weiss said.The phone was moving, but no one was answering.
"We actually were looking at her phone while they were moving her body ... probably to take her to the morgue."
Veronika was one of six college students killed by Elliot Rodger, who was bent on killing beautiful women and popular men after years of self-described rejection and jealousy.
The irony, Weiss said, is that Veronika was exactly the kind of person who would want to help Rodger.
"She was kind. She was the person who would reach out to the kids who weren't the popular kids, some of the nerdy kids, some of the kids that were a little bit like this Rodger kid described himself as."
A cloud of grief has covered the scenic community of Isla Vista since Rodger killed six students from the University of California, Santa Barbara. Thirteen other people were wounded.
The university declared Tuesday to be a formal day of mourning, with a memorial service set for 4 p.m. PT (7 p.m. ET). Classes were canceled.
The University of California system will keep flags lowered to half-staff through Sunday, said Janet Napolitano, the UC president.
"During this terrible time for our UC community, I ask that you join me in the belief that the process of healing and reflection we will go through in the coming days will draw us closer as a university community. Together, we will get through this," Napolitano said.
Counselors are available on campus for anyone needing support, the university said.
The Associated Students of UCSB, a nonprofit student group funded by undergraduate fees, erected an "art wall of remembrance" in Isla Vista for anyone to write or post notes or artwork in colored chalk. Isla Vista is the off-campus student housing quarter.
"We really need the community to have a forum and a space to reflect on what's happened here," said Ali Guthy, president of the group.
Several students posted memorials on the wall.
"We won't forget you! You will always be in our heart! Stay strong!" wrote one person who signed his name as Jose G.
"Through your loss we will grow stronger!" wrote another person on a pink post-it note.
'We would die 100 times'
Kelly Wang and Johnny Chen can't understand why their son, George Chen, was stabbed to death by his roommate before the killer went on a shooting rampage. Wang said she would do anything to trade places with her son.
"We would die 100 times,1,000 times, but we don't want our kids to get hurt," Wang told CNN affiliate KABC, weeping.
"This shouldn't happen to any family. This should be the last one in the United States."
The plot may have been years in the making, but the killer gave just minutes' notice before he rained terror across Isla Vista.
Authorities now know Rodger's killing spree began before he even left home.
The 22-year-old former Santa Barbara City College student fatally stabbed three young men in his own apartment -- Chen, 19, Cheng Yuan Hong, 20, and Weihan Wang, 20.
Chen and Hong were the attacker's roommates, and Wang was visiting.
A friend of Rodger's family said Rodger recently had a feud with his roommates, complaining to his landlord that they were too noisy and played lots of video games.
The assailant himself outlined his plan to kill two roommates in a 137-page manifesto.
"I'd even enjoy stabbing them both to death while they slept," Rodger wrote.The manifesto chronicles his life from birth all the way to his planned "Day of Retribution."
On Friday, minutes before he killed two young women in front of a sorority house and shot a young man at a nearby deli, Rodger e-mailed his writings to two dozen people -- including his parents and at least one of his therapists.
"My orchestration of the Day of Retribution is my attempt to do everything, in my power, to destroy everything I cannot have," Rodger wrote.
"All of those beautiful girls I've desired so much in my life, but can never have because they despise and loathe me, I will destroy."
But it wasn't just beautiful girls he wanted to kill.
"All of those popular people who live hedonistic lives of pleasure, I will destroy, because they never accepted me as one of them," Rodger wrote. "I will kill them all and make them suffer, just as they have made me suffer. It is only fair."
Rodger's mother, Lichin, saw the e-mailed manifesto at 9:17 p.m. Friday. She went to Rodger's YouTube page and saw a disturbing video in which her son talked about "slaughtering" women at a sorority house at the University of California at Santa Barbara, family friend Simon Astaire said.
His mother called her ex-husband and 911, and the parents left from Los Angeles to Santa Barbara, the family friend said. En route, they heard there was a shooting. They later learned out their son was the gunman.
Elliot Rodger was found dead after crashing his black BMW, a gunshot wound to his head.