He wasn't that smart according to people who knew him. See below:
Neuroscientists debunk idea Colorado suspect was supersmart
He was one of six students admitted to the University of Colorado's graduate program in neuroscience last year. He received a $26,000 federal stipend.
Jacobson told the newspaper Holmes "should not have gotten into the summer program. His grades were mediocre. I've heard him described as brilliant. This is extremely inaccurate."
He said Holmes' high school transcripts showed Bs and no advanced-placement classes. He was accepted to the camp because he had done computer programming, Jacobson said. He was never Holmes' mentor, he said, but Holmes worked in his lab to write a computer code for an experiment Jacobson was working on. He told the newspaper Holmes never finished it.
"What he gave me was a complete mess," Jacobson says.
Holmes' résumé suggests he was trained in dissection of birds and mice, performing chemistry tests and attaching small gene tags to cells to target them for treatment.
"Recipe-book stuff, literally, that every biology student should learn," Eagleman says. As for the grant, Eagleman says, "Holmes is being depicted as some sort of brilliant researcher who won a rare grant, but there are thousands of research students in this country with such grants. Everyone has one. There is nothing elite about it."
Holmes had difficulty with a June 7 preliminary exam, given orally by three university faculty members. It is designed to evaluate students' knowledge at the end of the first year. Three days later, Holmes dropped out.
http://www.usatoday.com/news/nation/story/2012-07-24/john-holmes-smart-academics/56467518/1?csp=hf