The murderous career of John George Haigh is an object lesson in the importance of forensics in obtaining convictions. Haigh disposed of the bodies of people he killed by dissolving them in baths full of acid – he believed that the police needed a body in order to convict.
He was wrong, of course – although police originally began investigating him based on the items he stole from his victims, an analysis of the residue in his acid bath revealed three human gallstones and part of of denture. Haigh was arrested, and confessed to nine murders although he was convicted of only six. He was hanged in Wandsworth Prison, an execution that caused considerable controversy at the time (for its method – his guilt was not contested).
By Sussex Constabulary – Police photograph taken at Horsham Police Station, 1949, taken in the same session as Oates, Jonathan John George Haigh, the Acid-Bath Murderer: A Portrait of a Serial Killer and His Victims, Barnslesy, Yorks: Pen and Sword Crime, p. 147 ISBN: 978-1-78346-214-8. This particular file was found on blogspot.com., Public Domain, Link
As mentioned in:
Acid Bath Vampire — Macabre
Make Them Die Slowly (John George Haigh) — Church of Misery