James Holmes' recently released notebook shows the Aurora, Colorado shooter's horrifying plans for mass destruction.
Holmes, 27, pleaded not guilty by reason of insanity to over 160 charges.
According to CNN, defense attorneys claim Holmes suffered a psychotic meltdown when he reportedly killed 12 people and injured 70 more at a packed midnight showing of "The Dark Knight Rises" in July 2012.
Prosecutors presented the 29-page spiral notebook, which begins with a group of stick figures being killed.
The prosecutors argue this evidence proves a significant amount of planning went into the Colorado massacre.
Holmes wrote about how he developed an "obsession to kill" during childhood and was motivated to become violent by a "lifelong hatred of mankind," Yahoo! News reports.
He mulled over numerous weapons such as nuclear bombs.
In the notebook, he also debated whether to carry out the attack at an airport or movie theater, but ultimately, he decided against the former because he didn't want to be known as a terrorist.
He also wrote,
Holmes made detailed sketches of the theater and listed the pros and cons of staging attacks in different rooms.
Additionally, he estimated how long it would take for first responders to arrive and how many people he could probably kill before getting caught, according to the New York Daily News.
Much of his writing focused on his own mental illness.
He referred to himself as "divided," wrote "Why?" hundreds of times and listed 13 health conditions, including schizophrenia, he believed he suffered from.
The notebook was addressed to his mom, dad and sister. He mailed the book, however, to his psychiatrist, Dr. Lynne Fenton, at the University of Colorado.
It was found in a campus mailroom a few days after the attack and contained $400 worth of burnt bills.
Prosecutors are pursuing the death penalty but must reportedly prove Holmes understood the difference between right and wrong.
Citations: In notebook read to jury James Holmes wrote of obsession (CNN), James Holmes describes obsession to kill in notebook (Yahoo! News), Chilling notebook shows broken mind of Aurora shooter James Holmes (New York Daily News)