12 people were killed after a man dressed in black and wearing body armour and a gas mask, claiming his was the Joker, opened fire on the people.
US President Barak Obama is set to meet victims of the Batman theatre massacre that left 12 people dead in Friday's shootings. Among the dead were a six-year-old girl whose mother was also injured and two US servicemen.
According to the White House, Obama will be meeting families of the victims and local officials in Aurora, near Denver where James Holmes, 24, is said to have opened fire during a packed midnight screening of "The Dark Knight Rises."
Meanwhile, police in Aurora have dismissed suspicions that another person helped in the shooting.
British actor Christian Bale, who plays Batman in the last Batman trilogy, expressed his sorrow at the shooting. The studio behind the movie said it was withholding box office data out of respect for the victims.
"Words cannot express the horror that I feel," British actor Christian Bale said in a statement. "I cannot begin to truly understand the pain and grief of the victims and their loved ones, but my heart goes out to them."
Bomb experts spent Saturday inching their way into Holmes's apartment which was rigged with booby traps..
A small boom from a "controlled detonation" was heard by reporters outside the apartment block and pieces of debris were blown out of one of the windows through which police had been assessing the booby trap set up inside.
Aurora police chief Dan Oates did nothing to hide his anger at what the authorities found inside the apartment.
"Make no mistake, this apartment was designed to kill whoever entered it. And who was most likely to enter that location after he planned and executed this horrific crime? It was going to be a police officer," he said.
"And if you think we're angry, we sure as hell are angry, about what has happened to our city, what has happened to these wonderful people who live here, and also what he threatened to do to one of our officers."
Authorities said Holmes bought more than 6,000 rounds of ammunition online, as well as four guns in the two months before the rampage.
The shooter, dressed in black and wearing body armour and a gas mask, burst into the theatre barely 20 minutes into the screening, throwing two tear gas-type devices before opening fire with several weapons.
Police arrested Holmes by his car at the rear of the theatre. He offered no resistance.
New York City Police Commissioner Raymond Kelly said Holmes had painted his hair red and claimed he was the Joker, Batman's sworn enemy.