Arlene Holmes of San Diego told ABC News that her 24-year-old son, James Holmes, is the man accused in this morning's massacre in Aurora, Colo., nine miles outside Denver.
The mother had awoken unaware of the news of the shooting. She immediately expressed concern that her son may have been involved.
"You have the right person," the mother said, speaking on instinct. "I need to call the police," she added. "I need to fly out to Colorado." Her son had recently moved to Colorado to pursue a PhD, according to reports.
Holmes was taken into police custody in the theater's parking lot shortly after the gunfire broke out around 12:40 a.m., authorities said.
Around daybreak, San Diego police officers were spotted in and outside of Arlene Holmes' residence in the Rancho Penasquitos area as media crews started to gather outside with video cameras.
Police Chief William Lansdowne said the officers were there to provide security to the Holmes family and to assist Aurora police by gathering information for that agency's investigation.
Shortly before 7:30 a.m., police were spotted escorting a man out of the home and whisking him away in an unmarked police sedan. There was no immediate word on where the man was headed or his possible relation to the alleged shooter, but he was carrying what appeared to be luggage.
The incident began when a gunman wearing a gas mask set off an unknown gas and fired into a crowded movie theater in suburban Denver at a midnight opening of the Batman movie "The Dark Knight Rises," killing 12 people and injuring at least 50 others, authorities said.
Moviegoers didn't know what was happening and some thought the attack was part of the show. Then they saw a silhouette of a person in the smoke at the front of the theater near the screen, pointing a gun at the crowd.
"I told my friend `we've got to get out of here,' but then he shot people trying to go out the exits," Jennifer Seeger told NBC's "Today." She said the shooter made his way up the aisle, firing as he went, saying nothing.
Federal law enforcement officials identified the suspect as James Holmes, a 24-year-old American.
Holmes is in police custody, and the FBI says there is no indication that incident is tied to any terrorist groups.
The federal law enforcement officials spoke on condition of anonymity to discuss an ongoing investigation