James Holmes, 24, was identified by two federal law enforcement officers as the man who opened fire during a screening of "The Dark Knight Rises" at an Aurora, Colorado, theater early Friday. At least 12 people were killed, Police Chief Dan Oates said. 
Police break the apartment window of James Holmes, the suspect of a movie theater shooting Friday in Aurora, Colorado. 
An ambulance is parked outside. Of the wounded, at least 20 were being treated at the University of Colorado Hospital, said spokeswoman Jacque Montgomery. "They're arriving by police, by ambulance. Some are walking in," she said. 
Agents search the suspect's car outside the theater. 
Police continue to investigate outside the Century 16 movie theater on Saturday. 
Aurora Police Department motorcycles escort a sand-filled dump truck containing improvised explosive devices that were removed from Holmes' apartment on Saturday. 
Law enforcement officers speak with Colorado Gov. John Hickenlooper, center, outside the appartment of shooting suspect James Holmes on Saturday, July 21, in Aurora. 
Law enforcement officers prepare to disarm the booby traps in Holmes' apartment on Saturday. 
Law enforcement officials tow cars outside of Holmes' apartment on Saturday. Police are attempting to disassemble various devices and trip wires set up in the apartment. 
Officers prepare to place an explosive device inside the apartment. 
Debris flies out a window, right, after law enforcement officers detonate an explosive device inside Holmes' apartment on Saturday. 
People grieve during a vigil for victims behind the theater where a gunman opened fire on moviegoers in Aurora on Friday. 
A woman grieves during a vigil for victims behind the theater. 
A distraught woman is counseled by Pastor Quincy Shannon, left, of the New Hope Fellowship and an unidentified advocate in front of Gateway High School in Aurora, Colorado, where the families of the missing are meeting following the shooting at the Century 16 movie theater. 
Lin Gan wipes away her tears as her mother, Juan Gan, guides her to their car after meeting with counselors at the Gateway High School in Aurora on Friday. 
Lin Gan, of Aurora, Colorado, holds back tears as she speaks to reporters about her experience in the Century 16 theater on Friday. 
People embrace before a vigil for victims behind the theater where a gunman opened fire on moviegoers in Aurora on Firday. 
The car belonging to the suspect is removed from behind the theater where the shooting took place on Friday. 
Investigators work on evidence near the apartment of James Holmes on Friday. 
Members of the Aurora Police Department SWAT unit walk near the apartment of James Holmes. Police have Holmes,24, of North Aurora, in custody. 
Television news crews gather in front of the home of Robert and Arlene Holmes, parents of 24-year-old mass shooting suspect James Holmes, in San Diego, California. on Friday. 
A popcorn box lies on the ground outside the Century 16 movie theatre. 
An NYPD officer keeps watch inside an AMC move theater where the film "The Dark Knight Rises" is playing in Times Square on Friday. NYPD is maintaining security around city movie theaters following the deadly rampage in Aurora, Colorado. 
Adariah Legarreta, 4, is comforted by her grandmother Rita Abeyta near the Century 16 Theater in Aurora. 
A cyclist and pedestrians pass a theater showing the latest Batman movie in Hollywood, California, on Friday. Warner Brothers said it was "deeply saddened" by Friday's massacre at a Colorado screening of "The Dark Knight Rises." 
Obama supporters observe a moment of silence for the victims at a campaign event at Harborside Event Center in Fort Myers, Florida, on Friday. 
Jessica Ghawi, an aspiring sportscaster, was one of the victims. 
A woman waits for news outside Gateway High School, a few blocks from the scene of the shooting at the Century Aurora 16. 
Aurora police chief Daniel J. Oates speaks at a press conference near the Century 16 Theater on Friday. 
Agents search the trash container outside the suspect's apartment in Aurora. 
A Federal ATF officer carries protective gear onsite at the home of alleged shooting suspect James Holmes. 
Obama speaks on the shootings at the event in Fort Myers. 
Moviegoers are interviewed at the Century Aurora 16. 
Officers gathered at the theater Friday. 
Investigators were a common sight at the theater Friday. 
Authorities gather at the shooting suspect's apartment building in Aurora. Police broke a second-floor window to look for explosives that the suspect claimed were in the apartment. 
Screaming, panicked moviegoers scrambled to escape from the black-clad gunman, who wore a gas mask and randomly shot as he walked up the theater's steps, witnesses said. 
University of Colorado Hospital spokeswoman Jacque Montgomery said that all of the wounded had injuries from gunshot wounds, ranging from minor to critical. 
A woman sits on top of her car near the crime scene. 
Police block access to the Town Center mall after the shooting. 
Witnesses told KUSA that the gunman kicked in an emergency exit door and threw a smoke bomb into the darkened theater before opening fire. 
What is believed to be the suspect's car is examined after the shooting. 
Repubican presidential candidate and former Massachusetts Gov. Mitt Romney delivers remarks regarding the shooting in an Aurora, Colorado, movie theater on Friday at a campaign event in Bow, New Hampshire. 
- Investigators gain access to booby-trapped residence of James Holmes, police say
- President Barack Obama to meet Sunday with victims' families
- City of Aurora holds a vigil Sunday as part of an effort to come to terms with carnage
(CNN) -- The man accused of opening fire in a crowded Colorado movie theater left a trail of evidence that police say suggests the rampage was part of a calculated plan that included killing anyone who tried to learn more about him in the aftermath of the attack.
The revelations raised new questions about a possible motive in the attack in the suburban Denver community of Aurora that shocked a nation. President Barack Obama was scheduled Sunday to meet with victims' families and get an update on the investigation.
Authorities have said little about what they believe was the motive of suspect James E. Holmes, though investigators say there is evidence planning was under way for up to two months before the early Friday morning attack that left 12 dead and 58 wounded at the theater.
Holmes, 24, is being held in connection with the rampage at the theater and the subsequent discovery of his booby-trapped apartment, which authorities believe he rigged before leaving for the Century Aurora 16 multiplex.
Holmes received a high volume of deliveries over the past four months to both his home and work addresses, which police believe begins to explain how he got his hands on some of the materials used in the attack and those found at his apartment, said Aurora Police Chief Daniel Oates.
"What we're seeing here is evidence of, I think, some calculation and deliberation," Oates said.
"We have the evidence of a deliberative process to commit this assault, and we have the evidence of a deliberative process in his mind to attack whoever opened the door of his apartment."
Police gained access Saturday to Holmes' apartment after intentionally detonating two rigged explosives.
Technicians, with the help of a robot, worked to handle traps, wires and possible explosive and incendiary devices, Jim Yacone, a special agent with the FBI, told reporters Saturday.
The operation proceeded with an eye toward preserving evidence, all of which will be sent to an FBI lab in Quantico, Virginia, Yacone said.
Hundreds of residents were evacuated from five buildings, including the modest, three-story brick building where Holmes told police he had rigged his top-floor, one-bedroom apartment with explosives. All occupants except those who live in the suspect's building were allowed to return home Saturday night, police said.
While the threat to the apartment building Holmes lived was eliminated Saturday, Oates said the residences were being kept out at least until Sunday as investigators work "to preserve evidence."
By early Sunday morning, at least 26 people remained hospitalized -- nine in critical condition -- in five area hospitals.
Aurora's residents, meanwhile, were grappling with the aftermath of the carnage.
President Obama was due to meet with the injured and the families of those killed Sunday night in Aurora, where the city was planning a vigil that was expected to draw various public officials.
Oates said the Century 16 multiplex would remain shuttered at least until Wednesday to give police time to complete the investigation inside and allow the suspect's defense team access by Tuesday.
Holmes, who is being held in Arapahoe County Jail, is scheduled to appear in court on Monday morning. The court file was sealed, according to a court order.
Investigators have said little about what may have led the suspect to open fire during "The Dark Knight Rises."
Witnesses described the gunman as wearing a gas mask that concealed much of his face and head.
Holmes' hair had been dyed red, and he told police when he was arrested in the rear parking lot of the theater minutes after the rampage that he was "the Joker," according to a federal law enforcement source with knowledge of the investigation. The source was not authorized to release details to the media.
The Joker has long been a fixture in Batman comics and was famously portrayed by Heath Ledger in 2008's "The Dark Knight," the predecessor to "The Dark Knight Rises."
Oates has declined to release details about Holmes' appearance other than to describe what he was wearing: a ballistic helmet and protective gear for his legs, throat and groin, black gloves and a gas mask.
He also said he would not release the booking photo "for investigative reasons."
CNN's Tom Watkins, Dana Ford, Carol Cratty, Ed Lavandera, Susan Candiotti, Joe Sutton, Mike Brooks, Sarah Aarthun and Jim Spellman contributed to this report.
