Evans and Gainey outline fifteen reasons why they believe Tumblety should be considered a top suspect in the Whitechapel murders:
Tumblety fits many requirements of what we now know as the ‘serial killer profile.’ He had a supposed hatred of women and prostitutes (the abortion with the prostitute Dumas, his alleged failed marriage to an ex-prostitute, his collection of uteri, etc.)
Tumblety was in London at the time and may indeed have been the infamous ‘Batty Street Lodger’ -- he therefore may have had fair knowledge of the East End environs.
Tumblety may have had some anatomical knowledge, as inferred by his collection of wombs, his ‘medical’ practice, and his short-term work with Dr. Lispenard in Rochester.
He was arrested in the midst of the Autumn of Terror on suspicion of having committed the murders.
There were no more murders after he fleed England on the 24th November, if one counts only the canonical five murders.
Chief Inspector Littlechild, a top name in Scotland Yard, believed him a ‘very likely suspect,’ and he was not alone in his convictions.
Tumblety was fond of using aliases, disappearing without a trace, and was the subject of police enquiries before his arrest.
Scotland Yard and the American police had been in touch numerous times concerning Tumblety’s flight from France to New York.
One of the three detectives inspectors assigned to the case was sent to New York at the same time, perhaps to pursue Tumblety.
Tumblety evaded capture in New York City once again.
Tumblety had the wealth necessary for frequent travel and could afford to change his clothes frequently should they have become bloodstained.
He was an eccentric; but shrewd.
He had a tendency toward violence at times, and his career may have included other offences both at home and abroad.
Several acquaintances of his in America believed it likely that he was the Ripper when interviewed in 1888.
There is a strong case to be made that he was indeed the Batty Street Lodger.
Still, there are many opponents who believe Tumblety’s status as ‘Scotland Yard’s top suspect’ is poorly deserved. They make note of the fact that Tumblety’s homosexuality would rule him out as a suspect, as homosexual serial killers are concerned singularly with male victims and would be uninterested in female prostitutes.
http://www.casebook.org/suspects/tumblety.html