Keith Hunter Jesperson aka The Happy Face Killer. Letter from author Jack Olsen who wrote the non-fiction true crime book titled 'I' about the case of serial killer Keith Hunter Jesperson. This letter to Jesperson was written the year before Olsen passed away on July 16, 2002. 
Original one page typed note from Mr. Olsen to Keith Jesperson hand signed, Jack. These types of written communications between true crime authors and the subjects they write about are extremely uncommon.