DENVER — James Eagen Holmes came from a well-tended San Diego enclave of two-story homes with red-tiled roofs, where neighbors recall him as a clean-cut, studious young man of sparing words.
Tall and dark-haired, he stared clear-eyed at the camera in a 2004 high school yearbook snapshot, wearing a white junior varsity soccer uniform — number 16.
The son of a nurse, Arlene, and a software company manager, Robert, James Holmes was a brilliant science scholar in college.
The biggest mystery surrounding the 24-year-old doctoral student was why he would have pulled on a gas mask and shot dozens of people early Friday in a suburban Denver movie theater, as police allege.
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 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 doctoral program at the University of Colorado-Denver but was in the process of withdrawing, said school officials, who did not 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 called ‘‘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’s 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, called himself ‘‘The Joker,’’ the green-haired villain from the Batman story, according to New York City Police Commissioner Ray Kelly, who said he had been briefed on the matter.
Investigators said there was no evidence of a link between Holmes’s motives and the movie that was being shown in the theater.
A federal law enforcement official, speaking on condition of anonymity because of the ongoing investigation, said Holmes bought four guns from retailers in the last two months.
Holmes bought his first Glock pistol in Aurora on May 22. Six days later, he picked up a Remington shotgun in Denver.
About two weeks after that , he bought a .223 caliber Smith & Wesson assault rifle in Thornton and then a second Glock in Denver on July 6, the official said.
A high-volume drum magazine was attached to the rifle, the official said.
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 [teammates] 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 Holmes gave no sign of being distressed or violent when they had drinks Tuesday night at a local bar.
After Holmes approached him ‘‘we just talked about football. He had a backpack and geeky glasses and seemed like a real intelligent guy, and I figured he was one of the college students,’’ Mitchell said.
When Mitchell saw Holmes’s photo after the shooting, ‘‘the hair stood up on my back,’’ he said. ‘‘I know this guy.’’
San Diego Superior Court spokeswoman Karen Dalton said there were no records found under his name.