John Wayne Gacy aka the "Killer Clown" and "Pogo the Clown" was a Des Plaines, Illinois serial killer convicted of 33 murders and who was executed by the state of Illinois via lethal injection on May 10, 1994. 

Prison mailed envelope from Gacy which he sent to a member of his legal team postmarked October 25, 1985.
Includes an original $30 money order receipt for funds which were sent by the recipient to Gacy.

John Wayne Gacy Legal Envelope and Money Order Receipt