PoA - Snape knew?

[Miles]

No: HPFGUIDX 143459

whizbang wrote:
>Exactly.  If you read GoF carefully, Snape knew that Fake Moody
> was Barty Crouch Jr and he didn't tell Dumbledore about that either.

Miles: 
Would you find me some evidence in canon for this? I recently read
GoF, and I never had the idea that Snape knew about the real identity of
Fake!Moody.

whiz:
> Snape is amazing!  But in a nutshell, I
> think Snape confunded Trelawney to produce both of her "prophesies"
> that his main motive is to destroy the marauders as well as both
> Dumbledore and Voldemort and return the control of the magical world
> to purebloods, as Slytherin desired.

Miles: 
For both theories (concerning Trelawny and Snape's desire to destroy
the marauders) I would like to see hints in canon?
Ok, Snape really dislikes the marauders, but in very different ways. He
hates Sirius, he feels guilty for James' death (or thinks he owes James' son
his life), he can deal with Lupin and he actually lives with Wormtail. But
trying to destroy these so different persons as a group of teenagers that do
not exist any more?
And Trelawny? I see nothing that supports this idea.

But your last annotation is simply wrong. Snape is a Slytherin, but he is
*not* a pureblood (as we know) - why should he act for purebloods ruling the
wizarding world?

Miles