Some more thoughts on the Fidelius Charm (was: Re: Question #3)

[kennyg1864]

No: HPFGUIDX 183420


  > Ceridwen:
> DD couldn't have cast the charm or he would have known that Peter was
> the SK, not Sirius. He would have had to know who he was binding in
> the thing, or he could not have performed the spell.

Good point--my mistake for not distinguishing between "good speculation"
and "bad speculation" during my recent research on the missing 24 hours.
:P

So then...who cast the FC?

This author of the article linked below makes the valid suggestion that
(for objects, at least, and maybe for people too) you cannot cast a FC
on something that doesn't belong to you (think about it).  She therefore
suggests that Lily herself (or perhaps James) cast the FC on "the
Potters in their house".

Note that unlike with Grimmauld Place, the FC was not on the house
itself--i.e., the house could still be seen, but no one could see the
Potters in it.

(an excellent essay on FC's, both on Grimmauld Place and on the Potters,
including how Hagrid could find the latter)

http://www.hp-lexicon.org/essays/essay-fidelius.html
<http://www.hp-lexicon.org/essays/essay-fidelius.html>

This also means that DD could know of the house's existence, but he
couldn't know that the Potters were in it, nor could he see them in it. 
He probably did know that was where they were *supposed* to be, as he
alone knew of Harry's importance (due to the Prophecy) and likely made
the suggestion to Lily to cast the FC and designate a SK.  It's just
that afterwards, he couldn't know for certain they were there.

(which itself implies that he also suggested to Lily that they not move
anywhere else, because (a) Harry wouldn't be protected and (b) DD
wouldn't know the difference between "moved away" and "not visible due
to the FC"!)

But that still begs the question, "How did DD discover/detect that
something had happened there on Oct 31?"  Either someone told him
(Bathilda via "remote Patronus", perhaps?), or he had something like a
"transmitting Sneakoscope" in place, with a receiver amongst the myriad
devices in his office.

We know it was a very quick notification, as Hagrid was able to get
there before Muggles could investigate the now-ruined second floor.

In any event, DD didn't know that Wormtail was the Secret Keeper, else
(as Ceridwen pointed out), allowing Sirius' imprisonment would have been
criminal.

kennyg1864, who thinks that Lieutenant Columbo could have figured this
out at the time, had someone had the presence of mind to call him in




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