Authorities said they found a Batman mask and a drawing of a game involving a serial killer in the apartment of Colorado theater shooting defendant James Holmes.

The discoveries were revealed Wednesday during a pretrial hearing on whether evidence seized from Holmes’ apartment can be introduced at his trial.

A Batman movie was showing at the suburban Denver theater where 12 people were killed and 70 others were wounded in the 2012 attack.

An FBI agent said the mask was found in Holmes’ apartment by a bureau-led evidence team.

The drawing involved an address in downtown Denver, Aurora police detective Thomas Wilson said. It was found on a page in a spiral notebook inside Holmes’ backpack.

Wilson did not elaborate, and neither prosecutors nor defense attorneys questioned him further about it.

It was the first public mention of the drawing in the 15 months since the July 2012 attack at an Aurora movie theater where 12 people were killed and 70 others were wounded. Holmes also sent a notebook that contained violent drawings to a psychiatrist before the shootings, Fox News has reported.

Holmes has pleaded not guilty by reason of insanity to multiple charges of murder and attempted murder.

Defense attorneys are asking the judge to throw out evidence seized from the apartment because the search began before police had a warrant. Prosecutors say explosives found there were so dangerous that police didn’t have time to wait.

The hearing is the latest in a round of sessions this month over evidence that could be used to strengthen or weaken Holmes’ insanity claim.

Even if some evidence is barred, prosecutors still have a strong case, legal experts said. The defense has acknowledged Holmes was the shooter but say he was in the midst of a psychotic episode.

However, without the evidence, prosecutors could have a harder job convincing jurors that Holmes was sane, which they must do in order to obtain the death penalty.