It occurred to me to ask why Snape, who knew Lily very well and had watched her become friends with James Potter and the other three Marauders, didn't himself take out Wormtail once it became known that Lily was in mortal peril? Wouldn't Snape have known that Lily and James being friends with Wormtail would lead to disaster if Wormtail wanted to endear himself to Voldemort (which he did, of course)? Why didn't Snape incapacitate Wormtail in some way, to prevent him from going to Voldemort with the information on the Potters' whereabouts? Even if Snape didn't directly know that Wormtail was the Potters' Secret Keeper, he might have guessed that Wormtail was in a position to potentially harm Lily. Snape knew, presumably, that Wormtail was a Death Eater.

So why didn't Snape take a more direct approach in protecting Lily, rather than seek her protection by proxy via Dumbledore?

  • And what sort of direct approach do you think he could have taken, short of following her around like a bodyguard?
    – Kevin
    Jun 9, 2012 at 17:19
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    Also, Snape had already turned, if he knew Wormtail was the traitor, he would certainly have told Dumbledore.
    – Kevin
    Jun 9, 2012 at 17:52
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    I think everyone that has replied has missed something: Sirius says to Pettigrew in PoA: "[The Death Eaters in Azkaban] all think you're dead, or you'd have to answer to them... they think the double-crosser double-crossed them. Voldemort went to the Potter's on your information... and Voldemort met his downfall there." Clearly, many of the Death Eaters did know about Wormtail and his treachery.
    – twoerd
    Feb 18, 2013 at 19:23
  • Yes, Snape must have known if everybody else did as well. The question remains unanswered in my point of view. @twoerd Nice quote, I've only just found it myself, and I came here to share it but you are two days ahead of me! I have some other quotes I found in PoA that I'm culminating into an answer to this question.
    – Sheph
    Feb 20, 2013 at 21:30

6 Answers 6


I believe it is quite obvious that Snape didn't know that Wormtail was a Death Eater.

  • If Snape had known, he would have told Dumbledore.
  • If Dumbledore had known, he would have told Sirius, Lupin, and the Potters.
  • If the Potters had known, they would obviously not have made Wormtail the Secret Keeper. (They might, if allowed sufficient time to calm down, have managed not to kill Wormtail outright. While it would have been obviously useful to keep Wormtail around and in the dark, so as to use him to feed bad intel to Voldemort, I don't know if either Sirius or James would have had the temperament for such duplicity.)
  • Furthermore, on the hilltop, Snape would've been sure to mention that Pettigrew needs to be isolated from the Potters immediately, knowing how close he was to the family. This would be especially true if Sirius's calculation that Peter had been passing information for about a year was correct, as Snape almost certainly would've have known of his involvement in that case.
    – CCHP
    Jul 6, 2015 at 4:26

What makes you think he knew who the spy was before Wormtail told Voldemort? Snape wasn't always Voldemort's right-hand-man, only after he became a double agent was he of great value to Voldemort, because of his position of being trusted by Dumbledore.

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    I didn't say that at all. I said, Even if Snape didn't directly know that Wormtail was the Potters' Secret Keeper, he might have guessed that Wormtail was in a position to potentially harm Lily. This does not read to me as an answer proper. It's a question to me with a clarifying statement about Snape's status, which doesn't address anything from my original question. I think it makes a great comment, but not an answer. :) I will try and edit my question so that it's very clear what I'm asking. Jun 9, 2012 at 17:15
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    Wormtail was James and Lily's friend, Why would Snape suspect Wormtail of treachery? Voldemort would most likely not have told anyone (including Snape) who the mole was.
    – Kevin
    Jun 9, 2012 at 17:18
  • Why would he suspect Wormtail of treachery? Because Wormtail was a Death Eater and presumably Snape knew this, being a Death Eater himself (I imagine Snape and Wormtail saw each other at DE meetings), Voldemort was obsessed with killing the child in Trelawney's prophecy and Snape had already figured out that Voldemort was targeting Lily and Harry, and Snape knew that Wormtail was the Potters' "friend." Snape also had a natural inclination to distrust and be suspicious of the Marauders in general. I'm asking, once Snape knew who was targeted, why he didn't put 2 and 2 together and make a move? Jun 9, 2012 at 17:25
  • "Because Wormtail was a Death Eater and presumably Snape knew this" - I don't think Snape did know this.
    – Kevin
    Jun 9, 2012 at 17:27
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    @Slytherincess Dumbledore suspected there was a traitor and was doing his best to figure out who. Voldemort certainly knew that and would want to keep the mole's identity a secret. And can you really see Wormtail saying to the rest of the guys "BRB, weekly Death Eater meeting. Back for dinner."
    – Kevin
    Jun 10, 2012 at 17:02

Wormtail was a trusted member of the Potter gang and was protected by the rest of the group. Even if he had known Wormtail was the Potters secret keeper, Snape couldn't attack him without incurring the wrath of the other three. After Wormtail was confronted by Sirius Black, Wormtail disappeared and any opportunity was lost, and considering the ongoing hate Snape felt for Black, Wormtail's part in Lilys death went undetected until it was revealed in the Shrieking Shack.


I think that, considering the importance of having a close and trusted friend of the people he was hunting turning traitor against them, Voldemort would have kept this information to himself and wouldn't have trusted anyone with it. The fact that Snape's hatred for Sirius increased after the Potter's death means that he obviously believed that Sirius was the one responsible for betraying them. The fact that Sirius was subsequently framed by Pettigrew for his 'murder' really condemned him in most people's eyes and he became prime suspect. Wormtail had disappeared and was thought dead by everyone (except Sirius who knew what Pettigrew had done and that he had been framed by him for his faked death). Voldemort was disembodied and in no position to contact his former followers to tell them about the part Wormtail had played. There was no reason for anyone to suspect Pettigrew. Snape was the one who told Voldemort of the prophecy and whilst he knew that the Potter's were being sought and he requested Dumbledore's help in getting them hidden, he would have thought that their friends would have helped protect them. Dumbledore didn't suspect Pettigrew and he would have been in close contact with the Marauders who had subsequently become members of the Order of the Phoenix and more in a position to notice anything suspect than Snape, a confirmed Death Eater would have been.

After Voldemort’s return and the subsequent revelation that it had been Wormtail who had been responsible, I’m sure Snape did want to kill him (as much as he would’ve wanted to kill Voldemort himself) but couldn’t because Wormtail was now ensconced as a Death Eater who had remained loyal and to attack him would have exposed Snape’s true loyalties and resulted in the failure of the ‘long game’ mission he was engaged in.


Wouldn’t Snape have known that Lily and James being friends with Wormtail would lead to disaster if Wormtail wanted to endear himself to Voldemort (which he did, of course)?

Part of the answer to this question in particular comes down to whether or not you believe Snape knew about Wormtail’s allegiance to the Death Eaters. If you choose to believe that he did not know, you can see some of the other answers here. I am going to dedicate this answer to defending the case that Snape did indeed know, and try my best to explain why I think Snape might not have known that the Wormtail’s double-agent role would have led to disaster.

First, as evidence that Snape knew that Wormtail was a Death Eater, I present a quote from the chapter The Servant of Lord Voldemort in Prisoner of Azkaban:

“You haven’t been hiding from me for twelve years,” said Black. “You’ve been hiding from Voldemort’s old supporters. I heard things in Azkaban, Peter. … They all think you’re dead, or you’d have to answer to them. … I’ve heard them screaming all sorts of things in their sleep. Sounds like they think the double-crosser double-crossed them. Voldemort went to the Potters’ on your information … and Voldemort met his downfall there. And not all Voldemort’s supporters ended up in Azkaban, did they? There are still plenty out here, biding their time, pretending they’ve seen the error of their ways. … If they ever got wind that you were still alive, Peter - “

Here, Sirius gives us undeniable proof that at least some, if not all Death Eaters were aware that Peter was a Death Eater. I think it’s perfectly reasonable to assume Snape knew as well.

We also know from Sirius (later in that chapter) that Wormtail was passing information to Voldemort for one year prior to the Potters’ deaths. It is unclear whether or not he was a Death Eater for all that time, but since he has a tattoo, he would have had to become one before Voldemort fell, but not necessarily before he became secret keeper (There was “barely a week” in between).

I don’t think Wormtail was seen as threatening to anybody, including Snape. Lupin thought Black was the traitor, presumably because of his family’s heritage. Black thought Lupin was the traitor, presumably because he was a werewolf. Nobody gave Wormtail a second thought. Snape may have known Wormtail was a Death Eater, but given the importance of the information Wormtail was relaying to Voldemort, Voldemort may have chosen to receive Wormtail’s information in private.

But even if Snape had known that Wormtail could have posed a threat to Lily, was he going to act on that and kill one of his fellow Death Eaters before Voldemort solidified his choice to Harry. Voldemort might not have liked that Snape kill his informant. Snape was most likely in a very high strung position. There is a chance Lily can survive if Voldemort chooses Neville, and if he kills Wormtail before that, what might Voldemort do to him? It is a tight spot to be in.

Regardless, Snape doesn’t find out that Lily is the target until Voldemort chooses between Harry and Neville, at which point, he immediately tells Dumbledore to protect them (as a last resort, because only Dumbledore can stop Voldemort in his mind), and then Wormtail is made secret keeper (unbeknownst to anyone but Sirius and James). Barely a week later, Wormtail tells Voldemort, and Snape is powerless to stop him at that point. Snape is also powerless to stop Voldemort once the decision to kill Lily has been made, because he doesn’t know Wormtail is the secret keeper.

Dumbledore doesn’t tell Snape how he’s going to protect the Potters (Snape is still a Death Eater), so Snape has no reason to tell Dumbledore that it was Wormtail. Once she dies, and Snape becomes a spy, there’s no reason for him to reveal Sirius’ innocence. He loathes Sirius. I kind of got the feeling Snape knew in the Shrieking Shack because I think he was listening in on the conversation for a little while before he entered the room. (The time between when they heard the noise, and when he actually enters) The two are meanwhile explaining there innocence, and Snape refuses to acknowledge them. He just wants both of them out of the way. I don’t think Snape was thick enough to not believe them.

  • One glaring problem with this line of reasoning: the Death Eaters in Azkaban knew about Wormtail because of his treachery. Before Voldemort's downfall, as far as we can tell, nobody (except Voldy) knew that Wormtail was a closeted Death Eater.
    – Martha
    Oct 19, 2015 at 14:31

I don't have the books in front of me, so I can't get the exact quote, but I'm pretty sure there's a line somewhere that said that only Voldemort knew who all of the Death Eaters were. If that's the case, then it's possible that Snape didn't know that Wormtail was a Death Eater until after Voldemort's rebirth.

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