Letter from Azkaban

Sirius Black has been in Azkaban for nearly 10 years. Somehow he has managed to get paper and is trying to write a letter but he writes it over time and in time is slowly starting to lose his mind due to the dementors constantly being by him. He writes the letter trying to keep his mind and not be insane. He writes it as more proof to himself that he did not take part in Lily and James death. But writing a letter with the cold chill of dementors always near presents a challenge and he starts to insist in his letter that he is innocent. for someone to just believe it.