 An 18-year-old gunman opened fire on a fourth-grade classroom, killing 19 students and two teachers. Police did not engage the shooter for more than an hour. Arredondo was the on-scene commander and later admitted he decided not to try and neutralize the shooter immediately. A report by the Justice Department found leadership failures may have led to some of the wounded students bleeding out. School security officer Adrian Gonzalez, one of the first officers on scene, was also indicted. Jack Callahan, Fox News.