Fidelius, Sirius and Dumbledore

[Alexander]

No: HPFGUIDX 33968

  Greetings!

  While re-reading Prisoner of Azkaban, a question had
crossed my mind. There are many paradoxes in JKR texts that
are mentioned in Steve's Lexicon, but I haven't found this
one there, so I put it here for discussion.

  There were not many people who knew that Potters are going
to hide by Fidelius Charm. Potters themselves, Sirius Black,
probably Lupin, Peter Pettigrew and Dumbledore. Even more,
Dumbledore was unaware of Peter Pettigrew participation, so
he thought that it was Sirius who was the Secret Keeper.

  Now reading 1st chapter of SS/PS. Dumbledore knows that
Secret has been broken due to treachery of Secret Keeper. He
thinks that Sirius is the Keeper (and hence the traitor).
But when Hagrid tells him that it was Sirius Black who gave
the motorcycle to Hagrid, Dumbledore shows no surprise, or
shock, or anything!

  How can Dumbledore be so ignorant about this news?

  Did he know _already_ that Sirius was innocent?

Sincerely yours,
Alexander Lomski,
(Gryffindor/Slytherin crossbreed),
who would love to read second edition of JKR series with all
errors fixed...

    - What are you asking me for? Do you want for someone to
    tell you what the Light is? Nobody will do! Everyone has
    his own Light - have you got your own? Then fight for
    it! Defend it, damn you!
        Sergey Lukyanenko, "Night Patrol".