AURORA, CO (NEWS1130) – New details have emerged surrounding the Colorado shooting suspect’s plan, following last Friday’s massacre in an Aurora movie theatre.

According to celebrity gossip website TMZ, James Holmes mailed his notebook to a University of Colorado professor more than a week before he allegedly opened fire during a midnight showing of “The Dark Knight Rises.”

However, the notebook wasn’t discovered until Monday, three days after the shooting which killed 12 people and injured 58.

Fox News reports it was full of details and drawings about people would be killed.

Both police and the FBI said the notebook was sitting in the mail room of the university since July 12th, eight days prior to the massacre. It was addressed to a professor psychiatrist who treated patients at the campus’ university psychiatry facility, but it’s unknown if the professor had any contact with the shooter.

The notebook was discovered after another suspicious package was delivered to the university earlier this week. That package turned out to be nothing.

Earlier this year, Holmes dropped out of the same university’s neuroscience doctoral program, where he had studied mental health issues.

Meanwhile, Holmes former teachers and classmates are still trying to come to terms with his actions.

“He excelled in academics, he was at the top of the class, and even back then he was ahead of every student,” said a male student.

“He was a clean-cut kid, he was well-dressed, he was articulate, he was a top, top student, he caused no trouble,” said a teacher who taught Holmes over 10 years ago.

“As a teacher, you’re thinking ‘this is one of my kids’ and then you also think ‘could I have done anything?’ or ‘did I see anything? Did I miss anything?’”

Holmes is expected to be formally charged on July 30th.

The Denver Post reports background checks for people wanting to purchase firearms in Colorado have jumped more than 41 per cent since last Friday’s attack.