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. 

Handmade Halloween card with a letter that begins on the inside and continues on a separate 8 1/2" x 11" sheet of white lined paper. The card is hand signed four times. Hand signed twice, DLR, and hand signed twice, Dennis.
 
The double sided sheet which the letter continues from the inside of the card and after reading the paper the letter BTK closes this letter on the back of the Halloween card which he made in prison.