let's play a game of "what if"!

[JadenCollins]

I agree with Pcdunn, it could be a pregnant woman.
He could cut her open and just take the baby/fetus out.
Probably write another letter, adding the fetus in a small box.
That would be the ultimate thing for Jack.
Something greater than what he did to MJK.

[Michael W Richards]

Interestingly there is one possibility nobody has suggested here - including me in the earlier response.

Jack could have decided to go after men...not necessarily male prostitutes (paging Cleveland Street), but the "Johns", especially if they were drunk.

We keep talking of the shock and horror of the crimes on the British public and the world, but can you imagine the real terror had Jack decided to show he did not let the sex of the victim dictate his actions. There is nothing in the case to suggest this, but there was always the possibility that he might have switched over.

I bet the police would have caught him then - after one or two killings with mutilations. There would have been even greater pressure to do so if men had become the victims.

Jeff

At one time I toyed with the idea of writing a fictional piece about these cases....after almost 30 years of study I should do something with this data...about a boyfriend of a victim trying to track down the killer by himself, and in the process, he becomes the only male victim of Jack. Yep....the idea is up for grabs. Although a finders fee or generous monetary gift is welcome.

[Mayerling]

At one time I toyed with the idea of writing a fictional piece about these cases....after almost 30 years of study I should do something with this data...about a boyfriend of a victim trying to track down the killer by himself, and in the process, he becomes the only male victim of Jack. Yep....the idea is up for grabs. Although a finders fee or generous monetary gift is welcome.

Hate to burst your "finders fee" bubble Michael, but I seem to recall there was a short story that ended that way. I can't recall the name of it, but if I find it I'll tell you.

Jeff

[Errata]

I feel like Jack is a mission oriented killer. He is punishing these women by the overkill on the throats, but the mutilations are business. The mutilations and the taking of organs is the point, the goal. I think Kelly was different because it was personal. He was experiencing personal feelings, not just the pursuit of his goal. So it was a horror show. But I don't think he would be compelled to repeat that kind of destruction without a personal connection. I think he goes back to an Eddowes style kill. Within five weeks of Kelly. And I think he would start devolving eventually, so sure of the rightness of his mission that he doesn't believe that people will think he's doing anything wrong. He would get less careful eventually. But not immediately.

[SirJohnFalstaff]

Hate to burst your "finders fee" bubble Michael, but I seem to recall there was a short story that ended that way. I can't recall the name of it, but if I find it I'll tell you.

Jeff

This is not far from the French movie "L'Homme qui voulait savoir" (the man who wanted to know). There was an American remake with Jeff Bridges and a not yet famous Sandra Bullocks. The US ending was quite different than the original.

[Syrius]

I'll play...

The sixth victim would have been much more in the vein of the first five, because I have him down as an opportunist. So prostitute, in their 40s, destitute.

He'd kill her outside, reasonably well hidden (Chapman/Stride type location) in Whitechapel.

The murder would have been a couple of weeks after the MJK killing, at a weekend, because whoever it was had a regular job.

He'd be as careful as before...which actually wasn't particularly careful. I know you said to leave pet theories, but I am seriously wondering whether as a serial killer he just got really, really, really lucky five times.