It was a writing tablet from inside the house, no question. An intruder could have used it, however.
The not totally conclusive part was that Patsy wrote the note. She could not be ruled out, some said, and some apparently believed she wrote it. But it was not something so exact that you could say she was fingered.
They could not prove she wrote it, because if they could have, she would have been indicted.
A perfect "did NOT write the note" was a score of 5. John scored 5. Patsy scored 4.8 or 9. Perfect match would have been 1. Patsy didn't score 100% innocent, but she certainly wasn't any where close to scoring guilty. IMO It just gave the media something to write about.
Thanks for the clariification, t. It's so long ago, that I just don't remember all the details and nuances. You're a blessing in the 'info dept'.