Dennis Lynn Rader is an American serial killer known as Wichita Kansas' "Bind Torture Kill" aka "BTK" who was convicted of 10 murders which occurred between 1974 and 1991. 

8 1/2" x 11" hand drawn map of Wichita and Park City on which BTK shows a friend of his his old stomping grounds and tells them to bring the map and hit the sites when they come to visit him. 
Hand signed at the close of the letter, Dennis.