It also is said to point a finger at two separate rappers, who are unnamed, and at Death Row Records security chief Reggie Wright Jnr, who is said to have ordered the drive-by shooting. Someone called 'Danny' is said to have handed the letter to a TV journalist.
The letter, which is unverified, says 'Danny' was 'told to take night out,' referring to Death Row Records boss Suge Knight, who many believe were behind Tupac's death. Knight was with Tupac in the Cadillac the night he was shot.
Tupac's last public photograph was taken as he was riding in the car with Death Row Records co-founder Suge on September 7, 1996, in Las Vegas.
Shakur was hit four times - twice in the chest, once in the arm, and once in the leg. He eventually died six days later on September 13.
The letter, written in chilling detail, details the assassination, and says that 'no one would have made it out,' going on about the background of a stolen rap song, a gang beating and the revenge murder.
It seems to point a finger at Death Row Records security chief Reggie Wright Jnr, and another up-and-coming rapper who cannot be named for legal reasons.
The letter says that Wright told the shooters where Tupac would be on the night of his assassination, and that the rapper opened fire.
Bond says: 'The story behind the confession letter is very simple. It was given to a Fox reporter who was very keen on the story.
'A big TV interview was set up by he was a no show and the letter was then given to Russel Poole (a former LAPD cop) and was put in a file and not looked at for a long time.
'When I saw it, the name of Reginald Wright Jrn just leaps out of the page. It reads he gave Tupac's location. My jaw just hit the floor when I read that'.
Bond is currently working on this third documentary covering the murder mystery.
He told the Sun: 'This letter is a bit like the Rosetta Stone - it makes a lot of other things make sense.
'This new documentary is important for all those involved in the killings, but in particular the victims and witnesses like Yafue Fula, the Outlawz rapper who was shot after the Tupac killing.
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