At least 12 people are dead and 50 are being treated at Denver-area hospitals -- the youngest a 3-month-old baby -- after a mass shooting at a showing of The Dark Knight Rises at an Aurora, Colo., movie theater around 12:30 a.m. local time. The suspect, identified by federal law enforcement officials as 24-year-old James Holmes, is in police custody. According to reports, Holmes kicked down an emergency door at the theater, threw in some type of smoke bomb and began shooting when moviegoers started to run. Holmes, who wore a bulletproof vest and was carrying a rifle and two handguns, reportedly fled to the parking lot and was confronted by police already at the theater for crowd control. It is the worst mass shooting in the U.S. since the 2007 shooting on the Virginia Tech campus. Twelve people ranging in age from 16 to 31 were taken to the Medical Center of Aurora with gunshot wounds and ranged from minor to critical condition. Three were treated for chemical exposure, most likely from tear gas. Seven victims are being treated at Denver Health; 21 people -- including the baby -- are at the University of Colorado hospital; and six people ranging in age from 6 to 31 were taken to the Children's Hospital Colorado.