“Once we barricaded the doors, we were essentially trapped where we were,” Byrd said in an exclusive interview with NBC News’ Lester Holt, speaking publicly for the first time since the riot. “There was no way to retreat. No other way to get out.”

“If they get through that door, they’re into the House chamber and upon the members of Congress,” added Byrd, who granted NBC News permission to use his name after authorities had declined to release it…

“I know that day I saved countless lives,” Byrd said. “I know members of Congress, as well as my fellow officers and staff, were in jeopardy and in serious danger. And that’s my job.”

Byrd said he had no idea if the person he shot was carrying a weapon. It was only later that night that he found out the rioter was a woman who was unarmed.

Asked why he pulled the trigger, Byrd said it was a “last resort.”

“I tried to wait as long as I could,” he told Holt. “I hoped and prayed no one tried to enter through those doors. But their failure to comply required me to take the appropriate action to save the lives of members of Congress and myself and my fellow officers.”