DENVER (Reuters) - Attorneys for accused movie theater gunman James Holmes are asking a judge to rule on the constitutionality of Colorado's insanity defense law before they decide whether their client should enter an insanity plea, court filings made public on Friday showed.
In a series of motions, public defenders representing Holmes said Arapahoe County District Judge William Sylvester needs to define how much information Holmes would have to disclose to court-appointed psychiatrists should he raise the insanity defense.
Colorado law says that a defendant who pleads not guilty by reason of insanity must cooperate with court-appointed psychiatrists, which defense lawyers said could violate Holmes' right not to incriminate himself.
Holmes, 25, is scheduled to enter a plea on March 12, but it is unclear if that date will hold in light of the defense motions.
He is charged with multiple counts of first-degree murder and attempted murder for the shooting rampage last July that killed 12 moviegoers and wounded 58 during a screening of "The Dark Knight Rises" Batman movie in Aurora, Colorado.
At a January preliminary hearing, prosecutors laid out their evidence against Holmes, detailing the lengths he went to in amassing an arsenal of firearms and explosives in preparation to commit mass murder.
Sylvester ruled there was enough evidence to bind the former University of Colorado neuroscience graduate student over for trial in the massacre.
Arapahoe County District Attorney George Brauchler has not formally indicated if he will seek the death penalty against Holmes. But last month he announced he had hired a death penalty prosecutor to work on the case.
The defense said in a separate motion that if Holmes is required to provide information, it could be used against him not only at trial but in sentencing as well, should he be convicted.
In the motion, defense lawyers said they believe that portion of the insanity law is unconstitutional, and they cannot effectively advise their client until that legal issue is resolved, which they said has not been challenged before in Colorado courts.
"No published Colorado case law has examined the current provisions ... regarding insanity and mental condition in the context of a capital case," the motion said.
Under Colorado law, prosecutors have 60 days to announce if they will seek the death penalty once a defendant enters a plea. Former Denver prosecutor Craig Silverman said defense lawyers will pull out all the stops to prevent Holmes from going to death row.
"The defense team is teeing up every possible appellate issue," Silverman said, adding that all three of Colorado's death row inmates were convicted and sentenced in the same jurisdiction.
The tragedy stands as one of the deadliest mass shootings in U.S. history and one that ranked briefly as the most lethal in 2012 - until 20 children and six adults were killed in December at a Connecticut elementary school.
(Editing by Tim Gaynor and Xavier Briand)