Frank DeAngelis, who as principal of Columbine High School helped the Jefferson County, Colo., community recover from the infamous shooting massacre in 1999, has announced that he will retire at the end of the 2013-14 school year. The Denver Post says that DeAngelis will complete 34 years of work at the high school--18 as principal. On April 20, 1999, 12 students and a teacher were shot to death by two students, who then took their own lives. After the tragedy, DeAngelis vowed that he would remain as principal until all the students in Columbine feeder schools at the time had graduated. He fulfilled that promise in 2012.