Decryption of the Zodiac Letter to Melvin Belli

On December 20th, 1969, a letter was mailed to Melvin Belli's residence at 1228 Montgomery Street in San Francisco, California (see attachments). The envelope also contained a piece of blood-soaked clothing. The author states in the first line, "Dear Melvin This is the Zodiac speaking." But was it a hoax? The police determined that the piece of bloody shirt material did indeed originate from the shirt worn by Paul Stine, the Zodiac Killer's last known victim who was murdered on October 11th, 1969, in San Francisco. As further proof of authenticity, the letter inside the envelope was written by the Zodiac Killer according to handwriting experts. So, what was the Zodiac Killer up to? And why would he send a letter to the high-profile attorney Melvin Belli? And why the bizarre message? For the first time, this letter is decrypted to reveal the hidden messages.