Snape's part in death of Sirius

[Anastasia]

No: HPFGUIDX 107714

Adi wrote:
>   According to Dumbledore, Snape first alerted the crowd at the 
> Grimmauld Place that Harry might be thinking that Sirius was taken 
> hostage by Voldemort at the ministry and then went to the Forest 
for 
> searching Harry. Now this explanation raises several doubts.
>  Firstly, why did Snape take so long to alert the Order? Assuming 
> that the guys who appeared at the ministry for Harry's resuce 
started 
> on the job immediately without dilly-dallying makes one ask, why 
were 
> they so late? We do not know how they reached the ministry 
ofcourse, 
> but I'm thinking they must either have used Floo powder or 
apparated 
> or used a portkey. 

Anastasia:
Well, I think there is nothing strange about that. 
Only as soon as Snape cannot find Harry in the forest does he 
understand that Harry must have found a way to go to the DoM. 
Snape knows that the students can't apparate, so how should they get 
to London? Umbridge wouldn't let them use the Knight Bus. Thestrals 
don't come to your mind as they are not likely to approach a person 
in the forest. 
IMO it took Snape a lot of time to 1) look for Harry 2) understand 
what happened 3) contact Headquarters.
Therefore, Lupin and the others left for London later than Harry.

Anastasia