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.

Birthday card send to Rader by a friend of his. BTK has hand dated the back of the card.
On the front of the envelope Rader has penned, "See back --->."
On the back is a handwritten message hand signed, Dennis.