The school resource officer at Marjory Stoneman Douglas High School has resigned, according to a Broward County Sheriff Scott Israel. Officer Scot Peterson resigned after he was suspended without pay. 'He never went in,' Israel said during a press conference Thursday afternoon. According to a timeline of the shooting on Valentine's Day, Israel said Peterson remained outside of the school building for almost four minutes during the shooting, which lasted six minutes. Peterson was the only armed officer at the school at the time of the shooting, which left 17 people dead, including 14 students. “I am devastated,” Israel said. “Sick to my stomach. He never went in.” Peterson was on campus through the entire shooting rampage, the sheriff confirmed. 'He was armed. He was in uniform.' Peterson was suspended without pay Thursday morning pending the outcome of an internal investigation. After authorities watched a video of the scene, took witness statements and Peterson's own statement, Israel said, Peterson then chose to resign. The investigation is continuing, but authorities do not plan on releasing the video at this time, and may never release it Israel said. He did describe what he saw on the tape, though, during the press conference, saying he saw the deputy arrive at the corner of a building on the campus of Marjory Stoneman Douglas High School, but he never went in. Israel said Peterson should have went inside the building and 'killed the killer.' It doesn't matter who goes in first when law enforcement arrives at the scene of an active shooter, Israel said. 'What matters is when we in law enforcement arrive at an active shooter, we go in and that's what should have been done.' Peterson did nothing for four minutes as he waited outside the building, the sheriff said. 'He took up a position. It looked like he was near the western most entrance into the building. 'He stayed where he was and never went in,' Israel said, even though he 'clearly' knew there was shooting underway. The alleged killer, Nikolas Cruz, 19, escaped after the shooting rampage by blending in with other students fleeing the building. He was captured a short time later in nearby Coral Springs and taken into custody without incident. Authorities said Cruz confessed to the killings and is facing 17 counts of premeditated murder.