Holmes' lawyers have indicated in court papers that they may instead pursue a defense of not guilty by reason of insanity. But that carries great risk: Prosecutors could argue that Holmes methodically planned his attack, casing the theater, stockpiling weapons and booby-trapping his apartment with explosives.
The judge newly assigned to the case, Carlos Samour Jr., warned defense lawyers that if they want to change Holmes' plea, the longer they wait the harder it will be to convince him to accept it.
If Holmes is found not guilty by reason of insanity, he will be sent to the state mental hospital, then returned to prison after treatment.
Colorado has three people on death row but has executed just one person over the past 45 years, in 1997.
Samour is also considering whether a New York-based Fox News reporter should have to testify about how she obtained confidential information about Holmes.
Jana Winter cited anonymous law enforcement officials in reporting that Holmes had sent a psychiatrist a notebook of drawings that foreshadowed the attack. Holmes' lawyers want to know who told Winter about the notebook, arguing that that person violated a gag order.
In the latest revelation in that case, Aurora Sgt. Matthew Fyles testified that a sticky note with a drawing was in the package sent to Dr. Lynne Fenton. Authorities previously did not confirm any drawings were inside but Winter's lawyer was prevented from asking questions about it because prosecutors said it wasn't relevant. Winter didn't mention a sticky note in her report.
The massacre helped lead to last month's passage of new gun control measures in Colorado, including a ban on the sort of high-capacity magazines that Holmes allegedly used to spray the theater with dozens of bullets in a matter of seconds. Seventy people were injured in the attack.
President Barack Obama was scheduled to visit Denver on Wednesday to highlight the legislation as part of his push for more gun control following a school massacre in Connecticut in December.
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