Technicalities can not only get you off. Sometimes they can send you to the gallows.
Q. The police suspect there's been a murder but no body has turned up anywhere. Does this mean they have to give up on the case? A. That's what 1949 London serial killer John George Haigh boasted to police after killing Mrs. Durand-Deacon, saying he had dissolved her remains in acid so the victim no longer existed, says E.J. Wagner in "The Science of Sherlock Holmes."
"You will find the sludge which remains on Leopold Road. But," he smiled confidently, "you can't prove murder without a body."
Haigh was mistaken on this point, as many others have been. The law does not require a corpse but rather a "corpus delicti," or "the body of evidence that establishes the crime has taken place." Not understanding this, Haigh made a full confession of the killing, plus five others, claiming he was a vampire in dire need of their blood. The police pegged his motive as going after the women's valuables. When experts examined the sludge, they spotted small polished pebbles that turned out to be gallstones of the late Mrs. Durand-Deacon. Also found were her dentures, bone fragments and part of a handbag. Later, the jury wasted no time in finding Haigh guilty and sentencing him to death.