Colorado theater shooter James Holmes detailed his "obsession to kill" — and how to carry it out — since he was a child, according to a passage written in a notebook he kept that was read to the jury at his trial Tuesday.
Prosecutors say the spiral notebook contains Holmes' detailed plan for the shooting that left 12 people dead and 70 injured and a description of his hatred of mankind.
At issue in his trial is whether Holmes was sane when he opened fire at a midnight screening of "The Dark Knight Rises," in Aurora, Colorado in July 2012.
Holmes dismissed biological warfare and serial murder in favor of a "mass murder/spree" in the notebook and considered attacking an airport but didn't want to be mistaken for a terrorist.
"The message is there is no message," Police Detective Sgt. Matthew Fyles said Holmes wrote.
The notebook was passed from juror to juror once Fyles' testimony ended.
In opening statements. defense attorneys said Holmes sensed something was wrong with his mind, even at a young age. They say the defendant decided to study the brain in the hopes of finding a fix for his condition.
Holmes lived with his parents Robert and Arlene Holmes in Rancho Penasquitos and attended Westview High School before setting off to study neuroscience at the University of Colorado.
In the notebook, Holmes detailed family therapy and self-harm that was dismissed as a paper cut.
He also wrote that his problems at school shouldn't be viewed as the reason for his attack, saying the "causation is my state of mind for the last 15 years."
Fyles also said Holmes also wrote that he needed to research firearms along with the law and mental illness.
Authorities also found a sticky note marked with a circle with the numeral one and the infinity sign inside -- the same symbol found on a calendar in Holmes' apartment on the date July 20. 2012, the day of the shooting.
Defense attorneys don't dispute that Holmes killed 12 people and injured 70 more when he slipped into a midnight premiere of a Batman movie, but they say his brain was so addled by schizophrenia that it distorted his sense of right and wrong and he had no control over his actions.