This is interesting. It won’t do anything to dissuade people who suspect him, and why should it? They don’t have any reason to believe him. But I think it’s interesting that he is aware of what people are saying about him on the internet and that he seems to not be very bothered by it, but more concerned about the person who sent him that document.
Ps. Not very "Zodiac" handwriting. I know it’s in cursive, but still. The last line is printed and not the same either.
I agree, duckking, it will not dissuade those who believe in Bruce’s guilt. However those same people have also said that Bruce would not answer any questions regarding the Zodiac murders. Apparently he will. This was written almost 10 years ago.
Did you notice the postmark date? As Ed Sanders would say, oo-ee-oo!
Good eye Seagull. 
Great find. Very interesting, indeed.
“…they may be dealing with one or more ersatz Zodiacs–other psychotics eager to get into the act, or perhaps even other murderers eager to lay their crimes at the real Zodiac’s doorstep.“ L.A. Times, 1969
