By swinging a pendulum he identified a 19 - year - old boy , a hunchback , as the culprit .
In 1692 , Aymar - Vernay was hired by authorities to locate a murderer .
By swinging a pendulum Aymar - Vernay identified a 19 - year - old boy , a hunchback , as the culprit .
In 1692 , Aymar - Vernay was hired by authorities to locate a murderer .