JACK the Ripper was a heavy boozer who was in and out of mental asylums, according to a new book.
Former police volunteer Sarah Bax Horton claims the name of the notorious serial killer was Hyam Hyams, a cigar maker who suffered with epilepsy.
The researcher - whose great-great-grandather was a policeman in the original investigation - says she has uncovered damning medical records that solve the case.
Sarah says medical records for Hyams, who lived at the centre of the murders, describe his “peculiar gait”after an injury left him unable to straighten his knees.
She told the Telegraph: “He was weak at the knees and wasn’t fully extending his legs.
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"When he walked, he had a kind of shuffling gait, which was probably a side-effect of some brain damage as a result of his epilepsy.”
Witnesses in the Ripper case described a man in his mid-thirties with a stiff arm and an irregular gait with bent knees.
Hyams, who was 35 in 1888, also matched the height and weight described by witnesses.
Sarah said the records also describe Hyams as being “particularly violent” after severe epileptic fits and claims his deterioration matches the increasing violence of the Ripper murders.
She said his decline could have triggered him to kill.
The murders also stopped in 1888 - around the time Hyams was picked up by police as a “wandering lunatic” and later committed at the Colney Hatch Lunatic Asylum in North London.
Jack the Ripper murdered at least five women in Whitechapel in the East End of London.
Sarah, who was a volunteer with City of London Police for almost two decades, only discovered her ancestral connection to the case during her research.
Her book One-Armed Jack: Uncovering the Real Jack the Ripper comes out next month.