A look behind the introverted life of James E. Holmes, a graduate student in the neuroscience department at the University of Colorado, Denver, before the shooting in Aurora:

“In the days after the shooting, faculty members and graduate students, in shock, compared notes on what they knew about Mr. Holmes, what they might have missed, what they could have done. Some said they wished they had tried harder to break through his loneliness, a student recalled. Others wondered if living somewhere besides the dingy apartment on Paris Street might have mitigated his isolation.

“At a meeting held at Dr. Ribera’s house, a student said, Barry Shur, the dean of the graduate school, said Mr. Holmes had been seeing a psychiatrist. When the authorities told him the identity of the shooting suspect, Dr. Shur said, his reaction was ‘I’ve heard his name before.’

“But all that came later.

“No one saw Mr. Holmes much after he left school in June.”