(CNN) Once again, gunfire erupted in a Colorado school, this time leaving one student dead and eight others wounded.

Tuesday's carnage at STEM School Highlands Ranch occurred miles from Columbine High School, yet another in a litany of tragedy -- two decades removed -- in which two students opened fire on classmates, killing 12 of them and a teacher.

"If you had suggested to anyone behind me, or in this room, that in 20 years in 20 miles we would have dealt with Columbine, Aurora theater, Arapahoe High School, the shooting of Zack Parrish and four other deputies, we'd have thought you mad, yet here we are again," District Attorney George Brauchler lamented Wednesday.

He added, "This does not define us, it won't today, and it won't tomorrow. These are abhorrent acts. Problem is when you get three, four or five of them within a 20-mile radius you begin to think they are less abhorrent. But I'm here to tell you, this is not who we are."

This is what Colorado has endured in two decades: