John Wayne Gacy aka "The Killer Clown" and "Pogo the Clown" who was convicted of murdering 33 young men and boys and burying 29 of them beneath his home and in his crawlspace in Des Plaines, Illinois. Gacy executed via lethal injection by the state of Illinois on May 10, 1994.
 
Envelope from the public defender's office in Des Plaines, Illinois addressed to John Gacy while he was housed on death row.