School gunman Karl Pierson liked debate, running, but acted "weird" at times

Centennial, Colorado (CNN) -- To many of his neighbors, Colorado school gunman Karl Pierson was the wholesome boy next door who liked achievement and ran on the cross country team. He even worked on an Eagle Scout project two years ago.

http://www.cnn.com/2013/12/14/us/colorado-school-gunman-karl-pierson/