OoP clues?

[Brett]

No: HPFGUIDX 158021

> Abergoat offers:
> I've heard some talk that if Sirius went through the veil with the
> mirror then Harry may be able to get advice for the land of the 
dead.
> JKR suggested the mirror might be used again <snip>

Argus Pyrites adds:

Well, I for one hope that this is handled delicately, if at all. 
I've enjoyed that death is death in Mrs. Rowling's world. The 
comment by Luna about hearing the voices beyond the veil, worried me 
then, and the mirror comment from the interview worries me more. 
Course, Harry broke his mirror... ('reparo' anyone?)

Another clue from OotP?? - Petunia's comment about that "awful boy" 
(As I'm new, it might be that this has already been well covered in 
a different thread (But I haven't read 'every post ever' just yet). 
I'll be brief and assume it has.)

If that comment does NOT refer to James(as I believe it does), then 
who? Snape? (second most likely?)Peter? Remus? Sirius?