Doesn't Voldemort know about Snape's loyalty?

[Brenda]

No: HPFGUIDX 107512

Boyd:
> Given that in OoP he has apparently been absent for some time and is a 
> source of considerable interest upon his return to Grimmauld, he must 
> be going somewhere far away. Perhaps talking to other possible allies 
> like Hagrid did?
> 
> Oh, no, did I just bump into another vampire discussion? 



Luckdragon64 writes:

O.K. I'll bite! 
"Severus, said Dumbledore, turning to Snape, "you know what I must 
ask you to do. If you are ready...if you are prepared..."
"I am," said Snape. He looked slightly paler than usual, and his cold, black eyes glittered strangely. "Then good luck," said Dumbledore, and he watched with a trace of apprehension on his face, as Snape swept wordlessly after Sirius.

Hagrid is sent to talk to his kind - the giants, and Snape is sent 
to talk to -?

Harry and Ron talking about Snape:
"Do you reckon he could've beaten you and Dumbledore there?" says Ron.
"Not unless he can turn himself into a bat or something," said Harry.
"Wouldn't put it past him," Ron muttered.

Did anyone happen to look at JKR's sketch of Snape on Pirate Monkey's Snape site??? Very Vampirish!!