Jack the Ripper
Ostrog is no ordinary offender, but a man in the prime of life with a clever head, a good education and polished manners, who would be certain to succeed in almost any honest line of life to which he might devote himself, but who, nevertheless, is an inveterate criminal...It is impossible to gauge the mental condition of a man of such intellectual and personal advantages, who would run the risk of ten years' penal servitude for such a miserable stake.
He spent the next ten years or so in various prisons. It worked to Ostrog's favor to occasionally show a little insanity during his trials so that his behavior could be looked at in a softer light. Many people believed that he was acting, but the ruse worked and he was transferred from prison to a lunatic asylum where he registered himself as a Jewish doctor.
At the time of the Whitechapel murders, he was wanted by the police for failure to report his whereabouts. Why was Ostrog even a suspect? He had claimed to be a surgeon; he was a known criminal; and he had been in a lunatic asylum. His lying had made him a suspect even though he was no more a surgeon than he was a Polish nobleman. His insanity was conjured up when it suited him.
It is worthwhile to compare Ostrog as a suspect anyway. He was not a violent criminal and there is no record that he ever assaulted a woman. More importantly, he was too old in his fifties or sixties in 1888 and he was too tall 5 ft 11 inches to fit any of the eyewitness descriptions of the killer.
Ostrog, like Druitt and Kosminski, are not plausible candidates and may reflect the propensity of high police officials to deny that they failed to catch such a high profile criminal despite all the resources they had to use.