I don't think that the torso murders were recognized as part of a pattern in the same way that we immediately recognize them today. Those that occurred at the right time were definitely drawn into the Ripper's orbit (in much the same way that the serial poisoner George Chapman was--and is--considered a Ripper suspect simply because he was in Whitechapel at the right time and he was demonstrably a sociopath. Nothing could be farther from Jack's MO than Chapman's and nothing less likely than that Chapman was Jack. But he's still given serious consideration because he was a serial killer who was Johnny-on-the-spot--and as identity theories go, that's one of the most rational.

(This is the sort of thing that makes me value M. J. Trow's gold-standard common sense.)