Dennis Lynn Rader is an American serial killer known as BTK, the BTK Strangler or the BTK Killer. Between 1974 and 1991, BTK killed ten people in Wichita and Park City, Kansas. Rader pleaded guilty and was sentenced to to 10 consecutive life sentences.
 
4" x 9" original mailing envelope sent to Rader. The sender's name and address and all of Rader's information appear on the acdtual envelope. They are only blocked out in the images here. The prison has stamped the date it was received on the front of the envelope.