Snape and Harry again.

[potioncat]

No: HPFGUIDX 113177

Alla:
> 
> Potioncat argued that Snape did not know about Harry's life at 
> Dursleys, but then was he briefed by Dumbledore about Harry's role 
in what is coming or wasn't he?

Potioncat:
When you get right down to it, we don't know what Snape knows.  Even 
if he knows that Harry is to be LV's downfall, does he know how the 
Durley's treated him?  

I'm not trying to justify Snape's behavior, just trying to 
understand it.