At approximately 1430 local time (2030 UTC) on 22 March 2021, a gunman opened fire inside a grocery store in Boulder, Colorado, a city located nearly 30 mi (50 km) northwest of Denver, the state capital. Hundreds of law enforcement officers arrived at the King Soopers supermarket, situated in a busy shopping plaza, following reports of an active shooter and advised individuals to avoid the area. A total of 10 people were killed in the event, including the police officer who initially arrived at the scene. Authorities arrested the suspected assailant, who suffered non-fatal wounds and remains in police custody. Local, state and federal officials have launched a probe to determine a possible motive for the shooting.