Reggie kray letter to.....?

im trying to trace down a letter from reggie kray to louise dunn (my mum) which was sent in 1991 while he was in prison. it explained what he was doing and what his thoughts was. she placed it in her kray brother books but my nannan loaned it to a friend without mum knowing when she asked 4 them back she said she "didnt see it in there" i know its a stupid question but any information would be much appreciated.