He was one of America’s most prolific serial killers, John Wayne Gacy, murderer of 33 teens and young men, executed for his crimes - but what was the motive?

The new documentary on ITVX, Devil in Disguise, explores Gacy’s clown connection, the trauma on his victims and families, prejudice in 70’s USA and glaring police failings. The killer protested his innocence to the end but his crimes are now textbook reading and possibly led to copycat killings by British serial killer Dennis Nilsen.