Forgery indicator 1: Not signed
Forgery indicator 2: Torn up (very strong indicator)
AND: The note was NOT found in his briefcase immediately after the "suicide", but a week later DID turn up..! Inside THAT SAME BRIEFCASE...!
Same for his car keys: NOT on his person, then magically appearing in his POCKET in the morgue. You hear that Arkansas banjo strummin'..? I do.
Oh! A news item from 7 weeks ago is that all the Foster documentation turns out to have recently disappeard from The National Archive..!!!