Background of Colorado shooting suspect full of contrasts

James E. Holmes is described by those who know him as a doctoral student who is clean-cut, quiet and responsible, an image difficult to reconcile with the same man who police allege opened fire in a crowded movie theater.

Days after the 24-year-old was arrested on suspicion of a mass shooting at the Century 16 multiplex in Aurora, Colorado, the portrait of Holmes that is emerging is as limited as it is confusing.

Pictures obtained of Holmes show a bright-eyed young man, who is tall with dark hair, which contrasts the description of the man by a law enforcement official who said he dyed his hair red and identified himself as "the Joker" to authorities after he was arrested early Friday morning for allegedly shooting people during a screening of the new Batman movie.

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By all accounts, Holmes is a bright student. He entered the University of California, Riverside, in 2006 as a scholarship student and graduated with highest honors with a bachelor's degree in neuroscience in 2010.

"Academically, he was at the top of the top," Chancellor Timothy P. White said.

UC Riverside police have no record of any contact with Holmes, the university said.

Neither did police at the University of Colorado School of Medicine, where Holmes enrolled in 2011 as a doctoral candidate in its neuroscience program at the Anschutz Medical Campus in Aurora, university officials said in a statement released Sunday.

In fact, the sole contact authorities in Colorado appeared to have had with Holmes was a speeding summons in 2011, according to Aurora police.

A syllabus that lists Holmes as a student at the medical school shows that he may have taken a class in which he studied topics as diverse as substance abuse, schizophrenia, depression and other disorders.

According to the document, he was to have delivered a presentation in May about microRNA biomarkers.

Though there are indications that something may have been amiss in Holmes' life in recent months.

He withdrew from the program in June 2012, though "he gave no reason for his withdrawal from the graduate school," said Jacque Montgomery, spokeswoman for the University of Colorado.

It is not immediately clear if Holmes, who also worked in a paid position in the university's neuroscience research program, was still employed there after withdrawing from the program.

Holmes received a large volume of deliveries over the past four months to both his home and work addresses, which police believe begins to explain how he got his hands on some of the materials used in the rampage and the subsequent discovery of his booby-trapped apartment, Aurora Police Chief Paul Oates.

The police chief has declined to release details about a possible motive or Holmes' appearance at the time of his arrest, citing an ongoing investigation. But he did say Holmes purchased four weapons and more than 6,000 rounds of ammunition in recent months.