FORT LAUDERDALE, Fla. – The school resource deputy at Marjory Stoneman Douglas High School did not enter the building where a former student killed 17 people last week, Broward County Sheriff Scott Israel said.

"He never went in," Israel said about the actions of Deputy Scot Peterson.

The sheriff said Peterson remained outside for at least four minutes during the six minutes that Nikolas Cruz opened fire inside the school.

"I think he remained outside for upwards of four minutes," Israel said.

Surveillance video showed that, despite being armed, Peterson stood outside the west side of the freshman building where the shootings occurred and remained there during the incident, the sheriff said.

When asked what Peterson was seen doing on the video, Israel said, "Nothing."

"I think he got on his radio at a point in time and he took up a position where it looked like he could see the westernmost entry into the building and stayed where he was," Israel said. "Never went in."

The sheriff said Peterson "clearly" knew there was a shooter inside.

Israel announced Thursday that Peterson resigned after being suspended without pay after an investigation.

"Devastated, sick to my stomach, there are no words," Israel said to describe his feelings when he learned Peterson did not enter the building.

"I mean, these families lost their children," Israel said. "We lost coaches. I've been to the funerals. I've been to the homes where they're sitting shiva. I've been to the vigils. It's just, there are no words."

According to Israel, action was taken against Peterson after interviews with witnesses and reviewing video of the shootings. Peterson had been the on-campus deputy since 2009 and was named school resource officer of the year for the Broward Sheriff's Office's Parkland district in 2014.

Peterson was placed on restricted administrative assignment and surrendered his BSO identification card and weapons Thursday. He was also prohibited from entering any BSO facility.

Two other BSO resource deputies, Edward Eason and Guntis Treijs, have been placed on administrative duties pending further investigation. Both deputies were involved in 23 calls for service at Cruz's home and may not have followed protocol.