(...)Holmes, who stands 6-foot-3, graduated from San Diego’s Westview High School in 2006, Poway Unified School District confirmed to Fox News. A gifted student, he studied neuroscience at nearby University of California-Riverside, where he graduated in 2010 with highest honors.

But in the age of widespread social media, no trace of Holmes could be found on Facebook, LinkedIn, MySpace, Twitter or anywhere on the web. Either he never engaged or he scrubbed his trail.

Anthony Mai, a 16-year-old who grew up next door to Holmes, described Holmes as a "solitary" person who largely kept to himself but his behavior was nothing out of the ordinary.

"He felt a little bit concealed, but it wasn't too much. It was alright" he said. "This is just a feeling in my gut, but I felt like he had something, like he was being picked on or something."

His father, Tom Mai, a retired electrical engineer, said Holmes was quiet.

"I said hello to him once in a while. He seemed to be a shy guy," he told reporters.

The bookish demeanor concealed an unspooling life. Holmes struggled to find work after graduating college, Tom Mai said.

Holmes enrolled last year in a neuroscience Ph.D. program at the University of Colorado-Denver but was in the process of withdrawing, said school officials, who didn't provide a reason.

As part of the advanced program in Denver, a James Holmes had been listed as making a presentation in May about Micro DNA Biomarkers in a class named "Biological Basis of Psychiatric and Neurological Disorders."