BOULDER, Colo. (AP) - The man accused of killing 10 people at a crowded Colorado supermarket last month armed himself with 10 high-capacity ammunition magazines, devices banned in the state after previous mass shootings, a prosecutor said Thursday.Boulder County District Attorney Michael Dougherty told reporters that Ahmad Al Aliwi Alissa, 22, possessed the magazines that hold more than 15 rounds unlawfully but that investigators don't believe Alissa purchased the magazines illegally.The high-capacity magazines were banned in Colorado after the 2012 mass shootings at a suburban Denver movie theater and at Sandy Hook Elementary School in Connecticut.RELATED: Suspected Boulder King Soopers gunman makes 1st court appearanceAlthough the.