The suspect's father, Bob Holmes, was seen leaving his family home in the community of Rancho Penasquitos with a packed bag just hours after learning that his 24-year-old son was accused of killing at least 12 people and wounding dozens of others in a movie theater in Aurora, Colorado.
Reporters caught up with him at the San Diego Airport Friday morning on his way to Colorado, but he had no comment.
Early Friday morning after learning of the shooting, a woman who identified herself to ABC News as Holmes' mother said, "You have the right person. I need to call police." Neighbors say Holmes' mother works as a nurse, while his father is manager at a software company.
Detectives have been questioning family members in San Diego, where Holmes grew up. Police say at this point, there is nothing to indicate that the Holmes family had anything to do with what happened in Colorado.
Holmes graduated from Westview High School in 2006, and he played junior varsity soccer. Back then, neighbors said he was known as Jimmy, and he didn't have a troubled past.
"I remember Jimmy as being really quiet, very smart," said neighbor Kim Goff.
"I saw him as a normal guy, just every day problems, every day things. I just didn't think that this would happen," said neighbor Anthony Mai.
In 2010, Holmes graduated from UC Riverside with a bachelor of science degree in neuroscience. UC Riverside Chancellor Timothy White said in a news conference that Holmes was a distinguished student during his four years there. He was also a member of the Phi Beta Kappa honor society.
"He was an honor student, so academically he was at the top of the top," White said.
University officials say counselors are available for staff and students who knew Holmes. They also say they are cooperating with Colorado law enforcement's investigation. University and Riverside police say Holmes had no record of run-ins with the law during his four years in Riverside.
He was a graduate student at the University of Colorado Denver until last month when he dropped out for unknown reasons.
"The Holmes family is very upset about all of this. It's a tragic event, and it's taken everyone by surprise," said San Diego Police Lt. Andra Brown.
Faced with dozens of cameras outside the San Diego home, the family said in a statement, "Our hearts go out to those involved in this tragedy and to the families and friends of those involved. Our family is cooperating with authorities in both San Diego, California and Aurora, Colorado. We are still trying to process this information, and we appreciate that people will respect our privacy."