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.