The Animagus Black (was: Faking Sirius' Death?)

[Inge]

No: HPFGUIDX 91506

--- In HPforGrownups at yahoogroups.com, "entropymail" 
<entropymail at y...> wrote:
>> I've been going over the whole "Sirius is dead" thing for a while, 
and wanted to put everything together.
 
Snip.....

>> Now, on to the duel between Bellatrix and Sirius in the Dept. of
Mysteries. Of course,  we are all aware of  the mysterious second
curse.  We all know that Bellatrix cast the first, which Sirius
dodged. But then "the second jet of light hit him squarely in the
chest." Not "Bellatrix's curse", not even a "green jet" which would
surely be an AK and would seal Sirius' fate. Just "a second jet". 

Snip....
 
Inge:
One thing that has kept me wondering is Bellatrix' words to Voldemort 
later when she tries to explain why she - and the rest of the DE's 
once again let Harry get away: "Master, I am sorry, I knew not. I was 
fighting the Animagus Black!" sobbed Bellatrix... "Master, you should 
know-" - and here she is - dang - interrupted by Voldemorts: "Be 
quiet, Bella!"

Now - what *I* want to know is

1) What is it that Bellatrix "knew not" ?

2) Why does she refer to Sirius as "The Animagus Black" instead of 
simply Sirius Black? Is it because 'the other' (Regulus) is still 
around somewhere and she doesn't want the names mixed up?

3) What is it that she thinks her Master should know but doesn't get 
the chance to say before he interrupts her?

Inge