Misinterpretation
Evidence in the case of British serial killer John George Haigh indicated that he decided to destroy the bodies of his victims with acid because he had the mistaken belief that, in the absence of a corpse, murder could not be proven because there was no "corpus delicti." Haigh had misinterpreted the Latin word "corpus" as a literal body rather than a figurative one.
Read more about this topic: Corpus Delicti