Out of the more than 100 Ripper suspects ever named, only one can be shown to have had a knife at the time of the murders, where they occurred - Francis Thompson. In 1888, he was a mentally ill, drug addicted man who carried a razor- sharp dissecting knife, kept from his years of studying medicine. He had already been in trouble with the police and had a history of arson, theft, and mutilating. His sole purpose for living in the Providence Row refuge, less than 100 yards from where Jack the Ripper victim, Mary Kelly, was killed was to find a prostitute who had humiliated him. He had already written about ripping their stomachs open.
But don't worry about any of that because it all comes down to interpreting his poetry.