Gacy later became known as the "Killer Clown" due to his charitable services at fundraising events, parades and children's parties where he would dress as "Pogo the Clown", a character he devised himself. John Wayne Gacy was an American serial-killer who also went under the nickname of the Killer Clown due to his charity work as a clown between his murder sprees, active from 1972 until 1978 he raped and murdered over 33 teenage boys and young men (six of them remain unidentified).
On May 10, 1994, Gacy was executed for his crimes and his execution was a major event with protesters from both sides of the argument attending, some displeased with the death-penalty and others gathering to taunt the serial-killer. He never expressed remorse, and his last words were: "Kiss my ass!".
After his death, Gacy's brain was removed and given to Dr. Helen Morrison, who was researching psychopaths. No abnormalities were found in his brain.