This question is not a duplicate of Why didn't Dumbledore prevent the prosecution of Sirius Black?.

I want to know what evidence Dumbledore had that Sirius wasn't lying in Harry Potter and the Prisoner of Azkaban. It can't be Leglimency because Sirius might have used Occlumency. Dumbledore wouldn't risk Harry and Hermione's life (there was a werewolf on the loose) based solely on a hunch. So Sirius must have given some concrete evidence. Remember that Dumbledore couldn't have spoken to Remus either. So why would he believe in the Animagus version of what happened when Sirius supposedly blew up the whole street? As far as I am aware, this isn't mentioned fully in the books.

Here are a few explanations:

1) Dumbledore realized that the whole story fitted together. It explained why Sirius had entered the castle but did not kill Harry. It explained why Sirius was on Ron's bed and not on Harry's. But there was the possibility that Sirius was mad.

2) He also realized why Buckbeak had disappeared earlier that night. But this can't be a sole reason for thinking some one is innocent. Maybe he used this in connection with (1).

So why did Dumbledore believe Sirius' version of events?

  • 3
    As Slytherincess says, Dumbledore trusted Harry and Hermione, not Sirius. Or at least he trusted the latter AFTER talking to the formers. It's not unlikely he already suspected Sirius was right, but he actually send H&H on the mission only after he spoke to them.
    – algiogia
    Commented Feb 23, 2015 at 15:24
  • @algiogia, but there's a problem with that theory too. How did he know that Harry and Hermione weren't confunded? Of course, Dumbledore probably can see through such things using his skills.
    – rah4927
    Commented Feb 24, 2015 at 7:37
  • Don't know. If we start with supposition we'd still be talking next year :) The only certain thing is that Dumbledore talks with Harry and Hermione and then they go to the rescue. Whether he thought Sirius was innocent even before is not stated in the books.
    – algiogia
    Commented Feb 24, 2015 at 8:42
  • Of course. But Snape suggested that they were confunded, and it was a good supposition, given the circumstances. Who knows?
    – rah4927
    Commented Feb 24, 2015 at 9:09
  • Because Dumbledore's awesome!
    – Mikasa
    Commented Sep 14, 2015 at 14:38

3 Answers 3


The Animagus transformation

Sirius could demonstrate the Animagus transformation for Dumbledore. Remember, unregistered Animagi are apparently quite rare - Sirius couldn't have simply faked it. This, as well as the backstory with Lupin that led to the them becoming Animagi (which Dumbledore knows is true, given the Whomping Willow incident) is a hell of a lie to come up with on the fly if you're a delusional killer.

Harry is still alive

After spending a unknown amount of time with Sirius, Harry still lives. This hardly seems like the action of the mad, devoted Death Eater out for Harry's blood. The only witness that Dumbledore has is Snape, but given his incredible bias Dumbledore seems to ignore his opinions. All he knows is that Lupin and Sirius were in the Shack with the trio. Remember, Dumbledore trusts Lupin, yet Snape was accusing him of helping Sirius. Unless Lupin was also guilty why was he with Sirius?


Small point, but we don't know Sirius could use Occlumency. Snape could, but Snape was heavily involved in that whole area of magic, especially given his Death Eater status. Besides which, he'd have to be damn good at it to get it past Dumbledore without Dumbledore knowing he was hiding something. And speaking of which...

Dumbledore's judgement

Dumbledore is repeatedly shown to be an excellent judge of character - he is almost always able to quickly understand the type of person he is dealing with (besides Moody, but I think that's a special case). His apparent naivety is shown to be anything but - consider his monitoring of Quirrel, or the scene where he tells Snape "you disgust me"...chilling. As Aberforth says, he's extremely gifted in the art of secrets and lies, as he'd have to be when running the counter-espionage movement against Voldemort.

Sirius' betrayal

An important point is that Sirius never defended himself. He was thrown in Azkaban without a trial while (apparently) going temporarily mad. No-one has ever heard his story! Considering Dumbledore's involvement with the Potters, he was well aware of the bond between James and Sirius. One of the reasons for the furious hatred of Black was that his betrayal was so unexpected, so unbelievable. Peter is far more likely to have cracked, and his heroic reputation is the product of his fake death, rather than any sentiment he earned while he was alive.

The Finger

It's a tiny but important detail. Sirius was arrested right after the murders - how would he have known the biggest part of Pettigrew they found was his finger? Fudge himself says it, but he was on the response team at the time. I highly doubt that part of the story was widely known (I don't believe it is ever mentioned by any other characters). But Sirius specifically states Pettigrew cut off his finger before faking his death.

  • I don't think Dumbledore is the type to use Occlumency in such an invasive manner, especially when there are plenty of other reasons to believe Sirius. But even if he was an Occlumens before, I doubt he's up to it after a decade in Azkaban.
    – alexwlchan
    Commented Feb 23, 2015 at 11:38
  • @alexwichan, I guess you mean "Leglimancy" in the first line. But what's so invasive about it? Especially if Dumbledore was having doubts, he would do anything he could to stop an innocent man's execution .
    – rah4927
    Commented Feb 23, 2015 at 11:42
  • @alexwichan I think it depends on the situation. A large part of Dumbledore's character is that he appears very kind and noble, but he's always ruthlessly realistic in his assessment of the world. I think if he judged it necessary he would use those abilities - the man could never quite escape the "for the greater good" motto that was the curse of his intelligence. But yeah the time in Azkaban would probably not help ones mental defences.
    – DavidS
    Commented Feb 23, 2015 at 11:44
  • 2
    If he had committed the murders he wouldn't have known about the finger. He blasts Pettigrew, street is destroyed, he stands laughing amongst the wreckage and body parts until he's picked up. Later they find only a finger. On the other hand, his story about Pettigrew faking his death backs up why he would know that detail and why they only found a finger - he'd even be able to say what finger it was!
    – DavidS
    Commented Feb 23, 2015 at 12:02
  • 1
    @alexwichan, leglimancy didn't seem to be traumatic when Dumbledore used it in HBP to find out Harry's mood in "The Seer Overheard".I always used to think that Harry's Occlumency lessons were traumatic because Snape was intentionally pushing the boundaries to teach him. Perhaps that deserves a question of its own.
    – rah4927
    Commented Feb 23, 2015 at 13:08

Actually, if you're going strictly by the books, it's not stated that Dumbledore believed Sirius per se -- it merely says that Dumbledore talked with Sirius. That is all Dumbledore says, when he enters the hospital wing to speak with Harry and Hermione.

It is only after Dumbledore speaks with Harry and Hermione that he expresses a belief in Sirius, so I think the better question is Why did Dumbledore believe Harry and Hermione that Sirius was innocent?

Dumbledore was a far more skilled wizard than Sirius, to say the least (Dumbledore was a far more skilled wizard than, well, anyone!). To say that he wouldn't have employed Legilimency against Sirius merely because Sirius might know Occlumency is short-sighted. First, there is absolutely no canon evidence that Sirius was an accomplished Occlumens. Canon shows us that Sirius was an accomplished Animagus. Second, even if your theory is correct, I'm willing to wager Dumbledore could have broken through any mental barrier Sirius might try to employ.

At the time Dumbledore spoke with Harry and Hermione, Buckbeak was presumably dead, not disappeared.

Dumbledore believed Harry and Hermione after speaking with them in the hospital wing.

  • 1
    I am not saying he didn't use Leglimency on Sirius(okay,I think I accidentally said that in the question,I am going to change it now). I am merely asserting that Dumbledore wouldn't risk Harry and Hermione's life(there was a werewolf on the loose) based solely on his Leglimency skills.
    – rah4927
    Commented Feb 23, 2015 at 11:22
  • Also,Buckbeak was not dead. Canon clearly gives evidence of the fact that multiple Harry's and Hermione's were on the ground that night.The book also explains that the executioner swung the axe into the fence in anger.Harry and Hermione didn't change time,they merely fulfilled the destiny of Buckbeak.
    – rah4927
    Commented Feb 23, 2015 at 11:28
  • @rah4927 Please don't change the question after answers have already been left. Commented Feb 23, 2015 at 11:33
  • I can't see how the word "presumably" has anything to do with contradicting my theory. Not that the theory is good, but it doesn't really contradict my theory.
    – rah4927
    Commented Feb 23, 2015 at 11:36
  • 4
    The time travel is circular (aka nothing changed) and we see the event from the other side. Ugly quoting follows - “Where is it? ” said the reedy voice of the Committee member. “Where is the beast? ” “It was tied here! ” said the executioner furiously. “I saw it! just here! ” “How extraordinary, ” said Dumbledore. There was a note of amusement in his voice. “Beaky! ” said Hagrid huskily. There was a swishing noise, and the thud of an axe. The executioner seemed to have swung it into the fence in anger.
    – DavidS
    Commented Feb 23, 2015 at 11:48

And the answer is...drum-roll please....

Peter Pettigrew shows up on the marauder's map which Lupin confiscated. Since the story is from Harry's point of view, we don't know what happens behind the scenes, but you know Lupin showed this to Dumbledore, which along with all the other great answers here is the piece of "proof" that Dumbledore needed to believe Sirius and go against the ministry of magic.

  • Escoce, Lupin is roaming the Forest as a werewolf at the time.
    – DavidS
    Commented Feb 26, 2015 at 16:47
  • Lupin is not always in werewolf form, and it the map did not necessarily have to be shared at just that moment.
    – Escoce
    Commented Feb 26, 2015 at 16:49
  • The question is asking why Dumbledore believed Sirius after talking to him in POA (which he obviously did, since he send Harry and Hermione back to save him). At that moment, yes, Lupin was in werewolf form and the map was a non-option. It's not asking what possible means of proof exist, given enough time (these suggestions wouldn't be practical anyway, since by the time Lupin returns to normal form Sirius would be dead)
    – DavidS
    Commented Feb 26, 2015 at 16:54
  • I think you are missing the point, that Lupin at any time before could and would have based on the levels of trust between lupin and dumbledore shared the map with dumbledore and showed him PP's footsteps on the map, to which dumbledore knowing the events of that past night and the evidence put forth known that peter was in fact NOT dead. Therefore, when sirius was speaking with dumbledore, dumbledore already had some information that allowed him to believe sirius.
    – Escoce
    Commented Feb 26, 2015 at 16:58
  • 2
    Are you going by the movies? (judging by the "PP's footsteps comment"). If so, I'm going by the book only - PP is never seen on the map prior to that night. Lupin only notices him on the map the on night of Sirius' attack. His reaction is to immediately run to the shack to confront them (not even stopping to take his Wolfsbane potion, nevermind tell Dumbledore). And the fact that he was too ashamed to tell Dumbledore the crucial info about the Animagus transformation makes it unlikely he'd show him the map for no reason.
    – DavidS
    Commented Feb 26, 2015 at 17:16

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