Snape's involvement in the murder of Sirius

[justcarol67]

No: HPFGUIDX 169119

Carol earlier:
> > Exactly. Voldemort knows as of the first chapter of GoF and
probably before that Wormtail is a rat Animagus ("You know that I can
disguise myself most effectively," Wormtail says). Surely, Wormtail
has told him the whole story of his escape from his former friends,
the dog Animagus and the werewolf. <snip>

> Jen:  It's always okay to speculate such a scenario and it could
very well be true.  The fact remains that we don't have Peter giving
this information to Voldemort anywhere in the story and Snape himself
says he passed information to Voldemort that helped dispose of Sirius
Black.  That may prove to be completely untrue but it's the only 
canon about the passing of information on Sirius.

Carol:
But we do have canon that Wormtail told the story of his escape(s) to
Voldemort though, granted, we don't have the details. He tells his
Death Eaters in the graveyard:

"And then, not even a year ago, when I had almost abandoned hope, it
happened at last . . . . a servant returned to me. Wormtail here, who
had faked his own death to escape justice, was driven out of hiding by
those he had once counted friends abd decided to return to his master"
(GoF Am. ed. 855-55). So it's not speculation that Wormtail told his
story to Voldemort. It's canon, as is Voldemort's knowledge of
Wormtail's Animagus form.

Black himself says in OoP that Wormtail will have told Voldemort about
his (Black's) Animagus form. True, he's speculating, but he knows
Wormtail well, and we also know from canon that Wormtail was passing
information about the Order to Voldemort before Godric's Hollow. We
know how much Wormtail knew about Black and the Potters; a great deal
more than Snape ever knew. And the *only* bit of information we
actually see in canon that Snape could have passed to Voldemort is
seeing Black transform from a dog to a man in Hogwarts.

I think the mere fact of telling Voldemort that Black was in England
was sufficient to claim a share in Black's death (to the psycho
murderer who might consider such a claim to be evidence of Snape's
loyalty to her master if she weren't convinced that Snape couldn't be
trusted). I suppose it's possible that Snape could have informed
Lucius Malfoy of Black's Animagus form, but Snape is talking about
passing information to Voldemort personally. It seems more likely that
*Voldemort* passed on the information about Black's Animagus form to
his Death Eaters (cf. Bellatrix's "I was fighting the Animagus Black,"
which is an odd way to refer to her cousin, however much she hates
him). And Snape took care to inform Black that Malfoy had seen him and
recognized him on Platform 9 3/4--his way of reminding Black of the
danger he's in should he decide to leave 12 GP again.

BTW, Jen, you're speculating, too, and the only canon I've seen is
Snape's vague claim to a Death Eater who distrust him that he's
provided useful information to Voldemort. In contrast, we have
Dumbledore's assertion that Kreacher provided the information you're
attributing to Snape.

Carol, conceding that we're all speculating at this point, but
thinking that canon supports some speculations more strongly than others