EMBED >More News Videos 17 dead in shooting at Marjory Stoneman Douglas High School, Steve Campion reports from Florida.

EMBED >More News Videos Florida shooting survivors meet lawmakers in Tallahassee.

FORT LAUDERDALE, Florida (KTRK) -- The school resource deputy at Marjory Stoneman Douglas High School has resigned following the school massacre, Broward County Sheriff Scott Israel confirmed.In a press conference Thursday, Israel said the armed deputy, Scott Peterson, was on campus during the shooting but failed to go inside to engage the accused shooter, Nikolas Cruz.The decision to suspend Peterson was made after witness statements, video and Peterson's own statement, Israel said."What I saw was a deputy arrive at the west side of Building 12, take a position and he never went in," Israel added.Instead of facing the suspension, Peterson decided to resign/retire.Cruz is accused of killing 17 people in the nation's deadliest school shooting since a gunman attacked an elementary school in Newtown, Connecticut.