Jurors in the Aurora Theater shooting trial began deliberating the fate of James Holmes on Wednesday morning after prosecutors and the defense delivered their closing remarks over whether or not the shooter was legally insane at the time of the attack.

Throughout the trial, the defense argued that the 27-year-old mass murderer was clinically insane when he opened fire at an Aurora movie theater showing "The Dark Knight" on July 20, 2012. As a result, 12 moviegoers were killed, while 70 others were injured.

The former neuroscience graduate student is facing 165 charges, including first-degree murder, attempted murder and an explosives offense. However, he has pleaded not guilty by reason of insanity. Now it will be up to the jury to decide whether to sentence him to the death penalty or prison.

According to the defense, the shooter suffers from schizophrenia and could not tell right from wrong when he intentionally killed people at the movie premiere. Therefore, they argue that he should not be found culpable.

"The evidence is clear that he could not control his thoughts ... he could not control his actions, and he could not control his perceptions," defense attorney Dan King said during closing arguments, according to CNN. "Only the mental illness caused this to happen and nothing else."

Prosecutors, on the other hand, accused Holmes of being a cold-blooded killer. Two court-appointed psychiatrists also made mention of their research that shows, though Holmes is severely mentally ill, he was legally sane when he planned and executed the massacre.

"Look at the evidence, then hold this man accountable," Arapahoe County District Attorney George Brauchler said. "Reject this claim that he didn't know right from wrong when he murdered those people and tried to kill the others. ... That guy was sane beyond a reasonable doubt, and he needs to be held accountable for what he did."

There is no word on when a decision will be reached.