A U.S. father waiting for word on his missing daughter during Friday's California shooting and stabbing rampage used an iPhone app that tracked her down — and led him to the coroner's office hours before authorities alerted him to her death.

Bob Weiss originally got a call from 19-year-old Veronika's friends the night of the rampage, saying they were unable to get in touch with the first-year University of California at Santa Barbara student.

The Weisses drove from their home in West Lake Village, Calif., to the hospital in the beachside college community​ of Isla Vista, about 100 kilometres away, where they were told Veronika had not been admitted.

"The woman at the emergency room checked with the sheriff and the sheriff relayed the message that we should wait at the hospital, which we did for about an hour," Weiss told an NBC affiliate in Los Angeles.  

After an excruciating wait at the hospital to find out what happened to his daughter, Weiss took matters into his own hands.

The Weiss family drove to one of the Isla Vista crime scenes, of which there were several, and used the Find My iPhone app to try to find their daughter.

Find My iPhone is a GPS tracking app that allows users to see where their device is on a map, and also track where it has been.

"The phone was communicating to us Veronika's exact whereabouts and tracked it directly to the coroner's office," he said. 

It was hours before authorities confirmed what they already knew.

Veronika was walking outside a University of California at Santa Barbara sorority house in college community of Isla Vista college community when she was gunned down by Elliot Rodger.

She was one of the six people who died in a shooting and stabbing rampage in Isla Vista, Calif., on Friday night.

Rodger drove around Isla Vista on Friday night, opening fire on random people and exchanging gunfire with law enforcement, before he crashed his BMW and shot himself dead. He killed six people, including three he stabbed before the drive-by shootings. 

Weiss spoke about his daughter before a memorial in her honour late Monday at Westlake High School’s aquatic centre, where Veronika had been a high school athlete. 

Weiss told the Los Angeles Times his daughter was a tomboy who played four sports at Westlake High School — cross country, baseball, swimming and water polo — while earning straight A's. Her strength was math.

"She wanted to be a financial wizard, and use her high aptitude with complicated math," Weiss said. "There was never a day I wasn't proud of her. Never a single day," he said.

Another of Rodger's six victims was identified as 19-year-old George Chen, originally from Ottawa