Ostrog was a swindler with a profuse police record who perpetrated multiple scams and frauds, but it was never proven that he committed any murders.

Ostrog emigrated to England, becoming known to the authorities in 1863 after committing his initial robbery at the University of Oxford using the alias of Max Grief.

After this seclusion, Ostrog continued to periodically leave and enter prisons for thefts, scams and frauds until 1904, the year any information about him ceases to be published.

[2] Even though in the memorandum of the Scotland Yard chief, Sir Melville Macnaghten, Ostrog was identified as a Jack the Ripper suspect, the investigators did not find evidence of violent crime in his past, much less homicide.

[3][4] In 2001, Philip Sugden, an expert on the Jack the Ripper case, located police records in which it was stated that Michael Ostrog had been charged with minor crimes and imprisoned in France in 1888, during the period of the Whitechapel murders.