Snape, Peter and Regulus

[Hagrid]

No: HPFGUIDX 136568

Snape, Peter and Regulus were all at Hogwarts about the same time 
and all joined the Death Eaters -

- but in what order?
- Did one introduce the other two?
- Was Regulus's death about the same time Snape had a change of 
heart about being a Death Eater?
- A common point of all three were Sirius and the Marauders (rival, 
member and brother of)

POSIBILITIES:

a) Snape was first. He recruited Regulus and Peter. It was a move 
directly against Sirius and James. If Snape was their superior in 
the DE, he may have been responsible for them. 
- So Snape may have been told to kill Regulus. 
- Peter had to go to Godric's Hollow with Voldemort because he was 
the Secret Keeper, but Snape may have gone to keep an eye on Peter. 
(You don't let a Marauder take your dark Lord to an enemy's place 
without added security or guards.)
- Snape would have known Peter in rat form and kept an eye on 
Scabbers since Percy brought him to school

b) Peter was first. Cornered by DE, he bargained to be spared if he 
was to be a spy and would prove his worth by recruiting other DE. He 
approached those against Sirius's ideals.

c) Regulus was first. He joined under Bellatrix and looked for some 
key students to recruit. Snape knew more Dark Arts than others his 
age. Peter was well placed in the Order.

d) They joined unconnected with each other. Regulus came through his 
aunt. Peter misread the map and turned left instead of right. Snape 
joined to get more frequent flyer points.

To find out:
- Accio Book 7! (and if that didn't work)
- Reply suggestions here.