A makes a call outside the University of Colorado Hospital on Friday, July, 19, 2012 in Aurora, Colo., Friday, July 20, 2012. A gunman wearing a gas mask set off an unknown gas and fired into the crowded movie theater killing 12 people and injuring at least 50 others, authorities said. (AP Photo/The Denver Post, Heather Rousseau) TV, INTERNET AND MAGAZINES CALL FOR RATES AND TERMS

AURORA, Colo. | One of the hospitals that took victims from a movie theater shooting that killed at least 12 and injured 50 is treating gunshot wounds from a high-powered rifle and buckshot wounds.

A man reacts after arriving at Children’s Hospital in Aurora, Co., Friday, July 20, 2012. At least 10 people were killed and about 50 were injured early Friday when shots rang out at an Aurora movie theater during a premiere showing of the new Batman movie. (AP Photo/The Denver Post, Craig F. Walker)TV, INTERNET AND MAGAZINES CALL FOR RATES AND TERMS
A makes a call outside the University of Colorado Hospital on Friday, July, 19, 2012 in Aurora, Colo., Friday, July 20, 2012. A gunman wearing a gas mask set off an unknown gas and fired into the crowded movie theater killing 12 people and injuring at least 50 others, authorities said. (AP Photo/The Denver Post, Heather Rousseau) TV, INTERNET AND MAGAZINES CALL FOR RATES AND TERMS

Children’s Hospital Colorado emergency room physician Dr. Guy Upshaw says he thinks the buckshot likely came from a shotgun, but the small, metal pellets can also come from explosive devices.

Six people were brought to Children’s, ranging from 6 to 31 years, and one has since died.

Two were shot by a rifle, three had buckshot wounds and one was injured by shrapnel.

A federal law enforcement official speaking on condition of anonymity because of the ongoing investigation said the gunman had an assault rifle, a shotgun and two pistols.