John Haigh commonly known as the Acid Bath Murderer, was an English serial killer. He was convicted for the murder of six people, although he claimed to have killed nine. He battered or shot his victims to death and used concentrated sulphuric acid to destroy their corpses before forging papers so he could sell the victims' possessions and collect substantial sums of money.
During the investigation, it became apparent that Haigh was using the acid to destroy victims' bodies because he misunderstood the meaning of the term corpus delicti, and mistakenly believed that, if the bodies could not be found, a murder conviction would not be possible. Despite the absence of his victims' bodies, there was sufficient scientific evidence for him to be convicted for the murders and subsequently executed.