Originally Posted by Fisherman
That is true, just as it is true that when we have two serialists in the same town, representing many common and peculiar traits in the way they do damage to their victims, they are to be expected to be the same man.
The first problem is that we don't know that there were two serial killers at work; the torso murders themselves could have been performed by one man, but they could have been committed by different individuals or even a syndicate.
The second problem is that, as Mike Richards has just pointed out, the behaviours vary widely, and there are major characteristics of the Ripper murders that are absent in the torso cases, and vice versa.
Third, even the perceived common traits are debatable.