DENVER — Thirty-three seconds after arriving at a suburban Denver home where a man had broken in and attacked an 11-year-old boy, police officers heard shots fired inside.

An armed man came into view, police said Thursday, refusing five orders to drop his gun. He started to come toward officers and raise a flashlight he held in his other hand.

An officer fired four rounds, killing 73-year-old Vietnam veteran Richard Black, Aurora Police Chief Nick Metz said in the department’s first detailed account of the shooting early Monday.