Dr. William Reid testified on May 28 that James Holmes was mentally ill, but still legally sane when he allegedly killed 12 people and injured 70 more during a mass shooting inside a movie theater in Aurora, Colorado, on July 20, 2012.
"My opinion is that he did not, is that whatever he suffered from, it did not prevent him from forming the intent and knowing what he was doing and the consequences of what he was doing," Reid stated in the Arapahoe County Justice Center in Centennial, Colorado, noted The Denver Post.
In addition to Reid's testimony, the jury watched some videos of Reid interviewing Holmes in a mental health facility in July 2014.
Reid added that Holmes had been taking "a fairly low dose" of medication for psychosis and depression at the time of the interviews, which were two years after the mass shooting.
Holmes has pleaded not guilty by reason of insanity — at the time of the murders — which could save him from the death penalty that prosecutors want.
The challenge for prosecutors is that they have to prove that Holmes was sane, per Colorado law, unlike most states and the federal legal system that force the accused person to prove he or she was not sane at the time of the crime.
Holmes' defense attorneys have claimed the accused shooter is suffering from a schizophrenic disorder.
The New York Times notes that a key piece of evidence is a spiral notebook that Holmes allegedly used to plan to shootings.
Holmes reportedly wrote that he was planning a "mass murder spree" and analyzed potential targets such as movie theaters and an airport.
The New York Times reports, "On a sketch of the Century 16 theaters he would attack, he noted that a police station was just three minutes’ drive away. He wrote that he had a 99 percent chance of getting caught."
While prosecutors point to the notebook as premeditated intent, Holmes' lawyers counter that it contains "a whole lot of crazy."
Prosecutors also claim that Holmes used a credit card, separate from a family card for necessities, to buy large quantities of guns, ammunition and explosives.