The man accused of shooting up a Colorado movie theater, dressed in full body armor with his hair dyed red in tribute to the comic book villain "The Joker," remains an enigma: an apparently quiet, studious doctoral candidate with next to no cyber footprint in today's social media-saturated culture.
James Holmes, 24, has no identifiable Facebook, Twitter or LinkedIn accounts and details provided by those who knew him are spare, making it difficult to paint a picture of a man accused of so horrific a crime, let along grasp his motive for allegedly doing so.
"People are using the word 'loner' to describe him, and that's not a fair representation," said a fellow doctoral student at the University of Colorado Anschutz Medical Campus who knew Holmes and agreed to be interviewed on condition of anonymity.
"He has friends. He's quiet and keeps a low profile, but we're all like that. We're PhD students. There's not a lot of time to do other stuff," the student said.
Police say Holmes opened fire on Friday at a midnight showing of "The Dark Knight Rises" at a movie complex in the Denver suburb of Aurora and killed 12 people and wounded more than 50 others.
Holmes was arrested in a parking lot behind the cinema moments after the shooting spree and is being held in solitary confinement to protect him from other prisoners. He is due to make an initial court appearance on Monday.
Raised in San Diego, Holmes played on his high school soccer team and went on to become an honor student at the University of California, Riverside, in Southern California, where in 2010 he got a degree in neuroscience.
Last year, he began a doctoral program in neuroscience at the University of Colorado Denver, but he was in the process of withdrawing from the program.
University spokeswoman Jacque Montgomery said Holmes was one of six doctoral students in neuroscience at the school to be funded by a training grant from the National Institutes of Health.
The grant is dedicated to supporting "outstanding neuroscientists and academicians who will make significant contributions to neurobiology," said Montgomery. Holmes did not give the university any reason for his abrupt withdrawal from the doctoral program last month. Police on campus said they had no contact with him during his studies.
One of the few possible online traces of Holmes was a profile on the dating and sex personals website Adult Friendfinder that celebrity website TMZ reported it had uncovered. A photo from the profile posted on TMZ showed a young man with his dark hair apparently colored red.
New York Police Commissioner Raymond Kelly, who has been in touch with Aurora police, has said Holmes' hair was painted red when he was taken into custody.
The profile TMZ uncovered has been taken down and the company that runs the website did not respond to a request to verify that the profile was genuine. TMZ said it had verified the profile with sources in the company.
Aurora Police Chief Daniel Oates told reporters on Friday that his investigators had not learned much about Holmes from their interviews with neighbors.
"He lived alone and kept to himself," Oates said.
One man who lived in his apartment building, but declined to be named, said he would sometimes try to say, "Hello," but never got a reply.
The first time shooting suspect Holmes walked into Original Aurora Liquor - about four blocks from his Aurora apartment - a year ago, a Palestinian immigrant who works behind the counter mistook him for an Iranian.
"Are you Iranian?" employee Joseph Nasser, 50, asked Holmes, who he said became visibly angry.
"What?! I'm no (expletive) Iranian," Holmes replied, according to Nasser, who has worked at the store seven years.
Nasser said Holmes looked like an Iranian customer who frequented the store at the time.
The next time he came in, Nasser said, Holmes apologized for his outburst. Nasser said Holmes came in a number of times over the past year, alone as best he could remember, and would usually buy a six pack of beer.
After that first encounter, Holmes was polite and unremarkable, never appeared inebriated, and did not buy alcohol in a quantity or frequency that would indicate any sort of drinking problem, Nasser said.
His building manager, who did not want to be identified, said she knew little about Holmes.
She called him a "normal, quiet kind of guy" who paid his rent on time and never made any trouble.
Arash Adami, 26, who is set to graduate with a PhD in neuroscience at the University of California, Riverside, said that in 2009 he had Holmes in the class he taught as a teacher's assistant. It was a class in which students examined cross-sections of dissected human brains, Adami said.
"He was a smart kid and he seemed personable with me," Adami said. "I remember the students who were disruptive, and I know he wasn't one of them."
The University of Colorado doctoral student said Holmes' fellow grad students were as shocked as anyone.
"We all think the same thing as everyone - that he was pushed past his breaking point," the young man said. "But I, personally, don't know what that breaking point was."
Holmes, he said, complained over beers about academic pressure, just like the other students did. But within his small circle of doctoral student friends and classmates, that was not unusual.
"He was very quiet, that's true. And he did not seem to me to be the kind of person who would take matters into his own hands like this."