By Keith Coffman
DENVER (Reuters) - Lawyers for accused Colorado theater gunman James Holmes said on Tuesday two homicide detectives may have perjured themselves when they denied leaking to Fox News details of his plan for the massacre, court documents show.
Prosecutors have said they will seek the death penalty for the California native if he is convicted of the July 2012 rampage in Aurora, which killed 12 moviegoers and wounded 70 others during a midnight screening of the Batman film "The Dark Knight Rises."
Holmes' lawyers concede he was the sole gunman, but say that the 26-year-old graduate student from the University of Colorado was in the throes of a psychotic episode at the time. He has pleaded not guilty by reason of insanity.
The defense team wants the judge to order a probe to trace the source of the Fox News story, which ran five days after the shooting. Citing two unnamed law enforcement officials, it said Holmes sent a psychiatrist a notebook detailing his plans.
Holmes' lawyers said in Tuesday's motion that since the few officers who knew of the notebook had all denied under oath being responsible for the leak, those who may have committed perjury included "two homicide detectives who played significant roles in the investigation of this case."
"The fact that a law enforcement official lied under oath in a death penalty case about a key piece of evidence is an incredibly serious matter," the defense lawyers wrote.
They noted that Arapahoe County District Court Judge Carlos Samour described the notebook as a "critical" piece of evidence.
The public defenders had previously sought a court order to compel Fox News reporter Jana Winter to reveal her sources, but the New York Court of Appeals ultimately sided with the journalist, and the U.S Supreme Court declined to review the case.
Prosecutors have denounced the allegations of a leak by law enforcement officials as "baseless," and have opposed the appeals by the defense for a special prosecutor to investigate.
Jury selection in the trial is set to begin in December.
(Reporting by Keith Coffman; Editing by Daniel Wallis and Jeremy Laurence)