Yes, I have. I take a keen interest in the Ripper case, and while I haven't read everything written on it, a major book by a major writer did get my attention.
She made an interesting observation: Walter R. Sickert was, besides an artist, an actor. He frequently traveled with various acting troupes throughout the British Isles. Some of the Ripper letters are sent from various locations around the nation, places where Sickert was acting at the time, and contain details only the Ripper would know (Cornwell claims to have authenticated most of the dates and locales).
She claims a lot of things that other researchers believe can't be claimed, and can even be shown to be wrong. She also assumes nearly all the Ripper letters were genuine, where again, most researchers believe the vast majority were fakes, and in fact, only one or two are given any credence at all by most experts (the Lusk letter being one of those few examples).
Portrait of a Killer Patricia Cornwell and Walter Sickert: A Primer
has a detailed analysis of Cornwell's claims by a Ripper expert.
The murders stopped when Sickert moved to France, which I find damning.
When Cornwell claims Sickert moved to France - something that can't be proven, although there is evidence to suggest it. Nowhere near as much as she claims though.
Thank you for the link. It is very interesting and pretty much indicates Sickert wasn’t even in London during four of the murders.
Reading about this case just emphasized how often someone is charged with a murder based on the slimmest amount of circumstantial evidence, like Scott Peterson, convicted of murdering his pregnant wife Lacey.
I’m always shocked at how someone can be sent off to death row minus incontrovertible evidence they committed the murder.