Law enforcement officials have charged a 21-year-old man with first-degree murder after he allegedly opened fire at a supermarket in Boulder, Colorado, on Monday, killing 10 people, including one police officer.

Ahmad Al Aliwi Alissa of Arvada, Colorado, was taken into custody Monday after officers responded to multiple calls of shots fired near a King Soopers grocery store and a call about a person possibly with a patrol rifle.

Police said they confronted Alissa inside the supermarket. The suspect was injured during an exchange of gunfire and transported to a hospital, officials said during a news conference Tuesday. He has been charged with 10 counts of first-degree murder and is expected to be transported to Boulder County Jail later Tuesday.