The filing, made public Tuesday, indicated the attorneys plan to file six motions dealing with issues that have not previously been considered by a Colorado court, The Denver Post reported.
"These motions involve very important and complex legal issues, many of which pertain to the death penalty and mental illness, and have never been filed or litigated before in the state of Colorado," the filing says.
Holmes admitted to killing 12 people and injuring 70 others in an attack on a movie theater, and pleaded not guilty by reason of insanity. His lawyers said he was in the midst of a psychotic episode at the time of the attack.
Meanwhile, attorneys argued Tuesday over the qualifications of chemical experts prosecutors plan to call at trial regarding evidence found in Holmes' apartment, the Post said.
Three FBI forensic examiners testified Tuesday they found substances including glycerin, black powder, potassium permanganate and polystyrene at Holmes' apartment, where investigators also found multiple bombs. The significance of the chemicals found was not reported.
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