The school resource officer who was on the campus of Marjory Stoneman Douglas High School last week during a fatal school shooting has resigned.

Broward County Sheriff Scott Israel announced Thursday that Scot Peterson turned in his resignation after being told he would be placed on leave without pay.

Israel said Peterson was on campus during the shooting and took up a position, but he did not enter the freshman building when the shooting was taking place.

Peterson was on campus, armed and in uniform during the shooting, the sheriff said.

Israel said he had decided to suspend Peterson, but "As is his right, Scot Peterson chose to resign." Peterson had met the requirements to retire, the sheriff said.

Israel said there was video showing Peterson's actions, but the video would not be released because the investigation is continuing.

He said the video showed Peterson take up a position outside the building, but "he never went in."

Israel said he was "devastated, sick to his stomach" when he found out about Peterson's actions. "There are no words."

"He should have went in," the sheriff' said. "Addressed the killer. Killed the killer."