Snape's knowledge

[Tim]

No: HPFGUIDX 45450

Something struck me as I was re-reading PoA and GoF.  Wouldn't Snape, 
as a former DE and spy, have knowledge that Pettigrew was a DE?  Even 
if he believed that Sirius was guilty of killing Pettigrew, he must 
have known that the stories surrounding the incident couldn't be 
completely true.  Or was his hatred of Black so great that he didn't 
care what the truth was?  

Tim A.