A 6-year-old video shows Colorado shooting suspect James Holmes as a thin teenager wearing an oversized shirt and occasionally breaking into a slight, shy smile.
ABC News aired the video Sunday showing Holmes speaking at a science camp at Miramar College in San Diego when he was 18.
His presentation is on "temporal illusion," which he defines as "an illusion that allows you to change the past."
He says he studies subjective experience, calling it "what takes place inside the mind, as opposed to the external world."
A woman who introduces Holmes says he wants to become a researcher and make scientific discoveries.
She says his dream is to own a Slurpee machine, eliciting laughter from the audience and a smile from Holmes.
Authorities said Holmes killed 12 people and injured 58 people at a midnight screening of "The Dark Knight Rises" on Friday.
He appears slightly nervous speaking to the group in the video, but also extremely intelligent, ABC reported.
This is how he was explaining his mentor's shared interest in fantasy versus reality in the video:
"He also studies subjective experience which is what takes places inside the mind as opposed to the external world. I've carried on his work in dealing with subjective experience."
By most accounts, Holmes lived the life of a normal teen, with a particular interest in science.
This was how he was introduced at the seminar: "His goals are to become a researcher and to make scientific discoveries. In personal life, he enjoys playing soccer and strategy games and his dream is to own a slurpee machine."
Though Holmes was apparently a gifted scientist who had received a federal grant to work on his Ph.D. at one of the most competitive neuroscience programs in the country, he was a loner who -- oddly for a young scientist -- seemed to have no Internet presence.