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.
A longtime neighbor in San Diego, where Holmes grew up, remembers only a "shy guy . . . a loner" from a churchgoing family. In addition to playing soccer at Westview High School, he ran cross country.
The bookish demeanor concealed an unspooling life. Holmes struggled to find work after graduating with highest honors in the spring of 2010 with a neuroscience degree from the University of California, Riverside, said the neighbor, retired electrical engineer Tom Mai.
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."
In academic achievement, "he was at the top of the top," recalled Riverside Chancellor Timothy P. White.
Holmes concentrated his study on "how we all behave," White added. "It's ironic and sad."
From a distance, Holmes' life appears unblemished, a young man with unlimited potential. There are no indications he had problems with police.
Somehow, the acclaimed student and quiet neighbor reached a point where he painted his hair red and called himself "The Joker," the green-haired villain from the Batman movies, according to New York Police Commissioner Ray Kelly, who said he had been briefed on the matter.
Julie Adams, whose son played junior varsity soccer with Holmes, said her son remembered little about the suspect, which was unusual for the tight-knit team.
"I don't think many of the kids knew him. He was kind of a loner," she said.
Jackie Mitchell, a furniture mover who lives several blocks from the suspect's apartment building in Colorado, said that he had drinks with Holmes at a local bar on Tuesday night, and that Holmes gave no sign of being distressed or violent.
When Mitchell saw Holmes' photo after the shooting, "the hair stood up on my back," he said. "I know this guy."
Holmes' family said in a written statement Friday: "Our hearts go out to those who were involved in this tragedy and to the families and friends of those involved. We ask that the media respect our privacy during this difficult time."