A while back I took a personal tour of the Black Museum in New Scotland Yard.
The curator has case notes and an interesting book published shortly after the retirement of (and I forget) one of the leading supervisors on the case. In the margin of the page that starts the chapter on the Ripper, in hand-written script in pencil, you can clearly read the “final chapter” (actually, a couple of paragraphs) that identify Aaron Kosminski as the Ripper and offers up proof.
When asked why he has not released this book and proof, the curator stated he has done so with various authors, but as he said, while the authors found the proof of the Rippers identity compelling and certainly close the case, it would hurt other books that they are writing. Why end a good run on a great conspiracy?
There are reasons the police did not arrest the Ripper, and it had to do with a number of things:
1) A Jew found to be the culprit would inflame already passionate anti-Jewish hostility in London and in Europe, and the commissioner at the time, under pressure from the politicians at the time, did not want to go there.
2) The Ripper was sent to a sanitarium where he was watched closely and upon his release into the custody of his brother, lived a quiet life of no further crime — he was watched constantly until he died.
3) There are surviving relatives and they are aware of the infamy of their ancestor and do not grant permission to release the record.
4) And finally, the museum is for learning not for voyeuristic purposes, and therefore will not release to the general public, as all the items in the Black Museum are officially evidence and held as such.
Not considered "compelling" because the details about the suspect, whether given by Anderson or Swanson are a very poor match to Aaron Kosminski.