DENVER (Reuters) - A former graduate student charged with shooting a dozen people to death at a screening of a "Batman" film in Colorado was due back in court on Monday as prosecutors seek to convince a judge they have enough evidence to put the accused gunman on trial.
Prosecutors will outline their murder case against James Holmes, 25, in a preliminary hearing that is expected to last a week and offer the public its first detailed glimpse into an investigation of one of the most chilling and deadly mass shootings in U.S. history.
After this week's proceedings, prosecutors will decide whether to seek the death penalty in the case.
The onetime University of Colorado doctoral student of neuroscience is charged with multiple counts of first-degree murder and attempted murder stemming from a rampage last July that left 12 people dead and 58 others wounded inside an Aurora, Colorado movie theatre.
The Denver suburb was shaken by gun violence again on Saturday when a lone gunman holed up in an Aurora townhouse shot three people to death and was killed hours later by police.
A wave of fatal shooting rampages across the country over the past year, led by the movie-house slayings in Colorado and last month's massacre of 20 children and six adults at an elementary school in Newtown, Connecticut, have reignited a national debate over gun safety.
Most of the evidence against Holmes has been placed under seal, and Arapahoe County District Judge William Sylvester has issued a gag order preventing all parties, including law enforcement, from publicly discussing the case.
A preliminary hearing allows prosecutors to present evidence so a judge can decide if there are grounds for a trial.
If the judge rules the case can proceed, Holmes will sometime later enter a plea. If he pleads not guilty, prosecutors have 60 days to notify the court and the defence whether they will seek the death penalty.
It also affords defence lawyers a sharper picture of the case against their client. And Holmes' lawyers are expected to call witnesses to testify about his state of mind in a move that could further portend the makings of an insanity defence.
Glimmers of such a defence strategy have emerged in hearings leading up to Monday's proceeding, including comments from Holmes' own lawyers suggesting he was mentally disturbed and had seen a psychiatrist.
Holmes, who has attended all but one court hearing since his arrest, has sat quietly throughout the proceedings as lawyers for both sides have wrangled over various legal issues.
Gone is the dyed red hair that the California native sported when he was taken into custody. His natural dark brown hair has since grown back, and in recent weeks he has appeared in court with a full beard.
Until last month's Newtown tragedy, the Aurora multiplex massacre ranked as the bloodiest U.S. shooting of 2012, one of the nation's worst years for gun violence in recent memory. Yet the circumstances of the movie killings stood out as a particularly shocking.
At an earlier hearing in the case, prosecutor Rich Orman said Holmes bought a ticket to the July 20 midnight screening of the Batman film "The Dark Knight Rises," and minutes into the movie left the theatre, propping open an exit door.
Holmes then donned protective ballistic gear and armed himself with numerous weapons, returned to the theatre, lobbed a smoke canister into the crowd and opened fire before surrendering to police, authorities said.
The day of the shooting spree, Aurora Police Chief Dan Oates told reporters that after Holmes was taken into custody, he told officers that he had rigged his apartment with explosives. Bomb squad technicians disarmed the booby-trapped dwelling before any of the homemade bombs detonated.
Legal analysts assume that Holmes will ultimately plead not guilty by reason of insanity, based on statements from his defence attorneys and in court filings.
Public defender Daniel King has said that his client suffers from an unspecified mental illness, and he has subpoenaed two witnesses for the hearing to testify about Holmes' mental state before the massacre, according to court documents.
Holmes could still waive his right to the preliminary hearing at the last minute, or his lawyers could raise the issue of their client's competency to proceed with the hearing, said Bob Grant, a former Colorado district attorney.
"Often, a defence tactic in capital cases is to delay the process as long as they can," said Grant, who prosecuted the only inmate executed in Colorado since the state re-instituted the death penalty in the 1970s.
Reporting and writing by Keith Coffman; Editing by Steve Gorman and Eric Walsh