"The Walk of Death"
Howard Unruh was the category defining American mass shooter. A WWII hero and paranoid schizophrenic, he had a firing range in his mother's basement, kept lists of which neighbors were due for retaliation, and was pretty much the prototypical ticking time-bomb killer in American media mass psychology.
There was a series of post-war "psycho" crimes that grabbed national attention and defined certain types. Unruh got the ball rolling. Others included Charles Whitman (spectacular TV age mass sniper attack... prefigured how we processed JFK assassination), Richard Speck (sexually motivated mass murder, fortunately a rarity), Charles Starkweather (teenage spree killing)
Anyway, one day Unruh walked out of the house and took a stroll through the neighborhood, shooting everyone he encountered.
It is striking how familiar his story reads after 64 years.
http://en.wikipedia.org/wiki/Howard_Unruh