A touch of evil finds role in psychiatric diagnosis

On Dr Stone’s scale, the most evil killers, such as the Moors Murderers, Ian Brady and Myra Hindley, are classified as ‘‘psychopathic torture murderers, with torture their primary motive’’. At the other end of the scale, the least evil criminals are those who have killed in self-defence.

Dr Stone’s scale also takes into account whether a killer has been abused, is a jealous lover of the victim, is a drug user, shows remorse or is power-hungry.

In the second study, Dr Michael Welner, a forensic psychiatrist and professor at New York University, sought to draw up a scientific definition of the ‘‘aggravating’’ factors in crimes that would determine whether or not a judge and jury can impose the death penalty.

On Dr Stone’s scale, Peter Sutcliffe, the ‘‘Yorkshire Ripper’’, who was convicted in 1981 of murdering 13 women, would be put on level 17 — ‘‘sexually perverse serial murderers’’, or five levels below the most depraved killers —because he did not torture his victims. Billy the Kid, the 19th-century teenage outlaw, is classified as level 6 (‘‘impetuous, hot-headed, without marked psycho-pathic features’’), while Jean Harris, a school headmistress who in 1980 murdered her lover in a fit of jealousy, is only level 2.