Rulloff was a brilliant yet utterly amoral murderer - some have called him a 'Victorian-era Hannibal Lecter' - whose crimes spanned decades, but by 1871 he was captured, chained in a cell - a psychopath holding court while curious 19th-century 'mindhunters' got to work.
From alienists (early psychiatrists who tried to analyse the source of his madness) to neurologists (who wanted to dissect his brain) to phrenologists (who analysed the bumps on his head to determine his character), each one thought he held the key to understanding the essential question: is evil born or made?
Expanding on her hit podcast, Tenfold More Wicked, acclaimed crime historian Kate Winkler Dawson draws on hundreds of source materials and never-before-shared historical documents to present one of the first glimpses into the mind of a serial killer - a century before the term was coined - through the scientists whose work would come to influence criminal justice for decades to come.