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. 
- A gunman went on a shooting rampage in Aurora, Colorado, killing and injuring many
- Carolyn Mears: It's like going through the 1999 Columbine massacre all over again
- She says there is much sympathy for survivors, but over time they will be left on their own
- Mears: For those who are experiencing trauma, remember that recovery takes time
Editor's note: Carolyn L. Mears holds a research appointment at the University of Denver. She is the author of "Reclaiming School in the Aftermath of Trauma: Advice Based on Experience" and "Experiences of Columbine Parents: Finding a Way to Tomorrow." She speaks internationally about trauma recovery, crisis preparedness and school safety.
Denver, Colorado (CNN) -- Five a.m., Friday, July 20. I stumbled downstairs to make coffee, turned on the radio for the news. Suddenly, the peaceful morning was shattered by reports of a shooting in nearby Aurora, where a lone gunman went on a rampage in a movie theater. Twelve people were killed and many more injured. All who were present, or responded to the scene, or had loved ones there, have experienced a traumatic event. Even those who hear about the event and identify with the victims may feel traumatized.
I know firsthand what it's like to go through such a shock. My younger son was at Columbine High School on April 20, 1999, when two students attacked the school and murdered 12 students and one teacher. Our intense grief was compounded by horror that this had happened in our safe little community. We felt vulnerable and powerless. At the time, we all hoped important lessons would be learned that could prevent future incidents like it. But in the years since the Columbine tragedy, rampage shootings seem to occur with regularity. Unimaginable situations are now all too imaginable.
News: Remembering the shooting victims through photos
After the Columbine tragedy, I sought to learn what helped and what hindered recovery in the aftermath of trauma. This is what I can tell you from my own experience and from my work with others who have survived horrific experiences and gone on to reclaim their lives.
Right now, people will want to know how to prevent this kind of tragedy, accompanied by the anxious fear that "this won't be the last." Sympathy will ripple across the country for those who were affected. Survivors and those who lost loved ones will be supported in their grief for a while at least.
News: Families receive tragic confirmations
But over time, a traumatized population will be left on its own with the implied message: It's time to get over it and move on. They will struggle to do just that, assuming that they should indeed be able to get back to normal. But this sad, sad message only breeds frustration and anxiety.
Those who lost someone to the shooting will experience immeasurable sorrow at the willful violence that stole away their loved one and destroyed his or her future. Those who were injured will carry physical reminders of their trauma. And all who were at the theater during the attack will have enduring memories of the event. Feelings of vulnerability may be compounded by survivors' guilt as they struggle with why they escaped when others didn't.
Belief blog: In Aurora, the agonized seek answers through faith
People respond differently to traumatic events, and the rate of recovery is individual. As Columbine High School's principal Frank DeAngelis often says, "It's a marathon, not a sprint."
Trauma is a natural, biological response affecting all areas of functionâ€"psychological, emotional, mental, physical, and spiritual. Don't be surprised if you have intrusive memories and trouble sleeping, concentrating and communicating. Other responses include grief, fear, confusion, hyper-vigilance, withdrawal from friends, anger, risk-taking, memory loss and depression.
You may feel distanced from others who haven't experienced a trauma. Past relationships may be challenged as new ones form with those who were there during the shooting. You may become defensive and driven to reclaim a sense of power over what happens to you.
News: Vigil held for shooting victims
Get help. Telling your story to a trusted listener can help you work through your experience. Don't deny that you are affected by the tragedy. Let people help you. Tell them what you need.
Be alert to extreme response such as substance abuse, or rage, or suicidal thoughts.
Be gentle with yourself; allow yourself time to process all that happened. A gradual return to a familiar routine is helpful. Find relief in things that brought you joy in the past.
Opinion: When it's not 'only a movie'
Above all, remember that recovery takes time. Don't assume things will go back to what was before. You have been changed -- as we all are by any unexpected life experience, but you may discover a greater appreciation for life and may treasure it more deeply.
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The opinions expressed in this commentary are solely those of Carolyn L. Mears.
