This week, two teachers have been killed on school grounds, allegedly by students.  Michael Landsberry, a teacher from Sparks Middle School in Sparks, Nevada, and Colleen Ritzer, a teacher at Danvers High School in Danvers, Massachusetts, are remembered as wonderful teachers, beloved by their students and colleagues.  Yesterday an 11-year-old boy brought several knives, a gun, and 400 rounds of ammunition to Frontier Middle School in Vancouver, Washington.  Two weeks ago, an ROTC student in uniform brought a gun into Hickman Mills Junior High School in Kansas City, Missouri, even though the school was equipped with metal detectors.  Thankfully, noone was injured in either of those cases.