The two police officers who fatally shot a machete-wielding man Oct. 5 on the University of Colorado campus were trapped in a stairwell with the man, and fired their weapons when he ignored their orders and quickly advanced on them, Boulder, CO, police Chief Greg Testa said.

In a presentation on his office's approach to issues including police bias and use of lethal force, Testa on Tuesday offered the Boulder City Council his understanding of the incident that left the man — ex-Marine Brandon Simmons, 28, of Thornton — dead inside the school's Champions Center earlier this month, reports the Daily Camera .

Fourteen CU officers and nine city officers responded that morning. Two of them — CU's Clay Austin and Boulder's Jason Connor — found Simmons trying to access the fifth and sixth floors of the Champions Center, which one can only do with a key card, Testa said. Neither Simmons nor the officers had key cards needed to exit the stairwell.

"When the confrontation occurs" between officers and suspect, the chief told the City Council, "the distances are very close and the officers are yelling at him to drop his bladed weapon. ... He cussed or made statements to them that would indicate he wasn't going to comply, and he started advancing towards them.

"Both the officers were trying to back down the stairs as they're yelling with him, and the distances got so close that they ended up shooting their weapons."

"Law enforcement officers do not shoot to kill somebody," Testa told the council. "They shoot to stop a threat."