How did Hagrid and Dumbledore know the Potters had been killed?

Question

In Harry Potter and the Sorcerer's Stone it says:

"No problems, were there?" [Dumbledore asked]

"No, sir - house was almost destroyed, but I got him out all right before the Muggles started swarmin' around. He fell asleep as we was flyin' over Bristol." [Hagrid said]

Dumbledore and Professor McGonagall bent forward over the bundle of blankets. Inside, just visible, was a baby boy, fast asleep. Under a tuft of jet-black hair over his forehead they could see a curiously shaped cut, like a bolt of lightning.

Sorcerer's Stone - page 11 - US Hardcover

How did Dumbledore - who I'm guessing dispatched Hagrid to go and survey the scene at the Potters' home in Godric's Hollow - know the Potters had been killed? Neither Dumbledore nor Hagrid were the Potters' Secret Keeper for the Fidelius Charm. How was Dumbledore alerted instantaneously that James and Lily had been killed, in order to be able to send Hagrid to the scene quickly enough that he was able to rescue baby Harry before the Muggles were alerted to the situation (which, to be honest, seems a bit unlikely if there was some kind of explosion, which it seems there was seeing as the house was "almost destroyed"). Heck, if the house next door to mine suddenly blew up, it would take me less than 10 seconds to get out onto my porch for a look-see!

How can these events logistically make sense?

ETA: Information on the Fidelius Charm.

When a Secret-Keeper dies, their secret dies with them, or, to put it another way, the status of their secret will remain as it was at the moment of their death. Everybody in whom they confided will continue to know the hidden information, but nobody else.

Just in case you have forgotten exactly how the Fidelius Charm works, it is

"an immensely complex spell involving the magical concealment of a secret inside a single, living soul. The information is hidden inside the chosen person, or Secret-Keeper, and is henceforth impossible to find - unless, of course, the Secret-Keeper chooses to divulge it" (Harry Potter and the Prisoner of Azkaban)

In other words, a secret (eg, the location of a family in hiding, like the Potters) is enchanted so that it is protected by a single Keeper (in our example, Peter Pettigrew, a.k.a. Wormtail). Thenceforth nobody else – not even the subjects of the secret themselves – can divulge the secret. Even if one of the Potters had been captured, force fed Veritaserum or placed under the Imperius Curse, they would not have been able to give away the whereabouts of the other two. The only people who ever knew their precise location were those whom Wormtail had told directly, but none of them would have been able to pass on the information.

J.K. Rowling's Website - The Fidelius Charm

I note that there is no canon evidence that Peter Pettigrew told anyone of the Potters' whereabouts except for Voldemort, and Voldemort, following the confrontation, wasn't exactly in the position to be playing Tellyfone with Dumbledore!

Answer 1

I don't think there is any canon info, but there are any number of magical distance observation methods he could have used:

• The alarm spell around Potter house (similar to the one that triggered near Hog's Head in DH when the trio arrived there).

• Watching from a portrait/photograph of himself at Potter's house (or other means - remember Sirius' mirror that he gave Harry to talk to him)

• Having a dead wizard portrait serve as observer

• Having some other alarm spell (e.g. something that monitors Potters' heartbeats).

Instantaneous communication is something normal for Potterverse (Dark Mark, Hermione's DA tokens, portraits, etc...). So are tripwire/alarm spells of all kinds.

Remember that Dumbledore was one of the most advanced wizards of his time, and was able to do extremely fancy magic, so combining SOME alarm/tripwire spell with a communication charm would have been easily within his capability.

And given the importance of the house/family (post-Prophecy), it's almost certain he'd have set something like that, especially being a paranoid nutcase diligent well-prepared-in-advance fellow that he was.

ETA: 09.01.12

SU: How did Dumbledore find out about what happened in Godric's Hollow?

MA:And what happened? There's this whole twenty four hours that people have been fantasizing about for years.

JKR: Yeah, I know. I've got a bit of problem with this myself, because every time I think it straight in my head I go back and look at what the fans are theorizing about, and I think "Yeah, maybe they've got a point." Dumbledore- Well there's an easy answer to how would Dumbledore know. Because you can- He? (laughs) You can. One can.

[SNIP]

Yeah, so okay. Obviously Dumbledore could cast a spell on a dwelling that would immediately alert him if something happened to it. So he could know instantaneously. That's not a problem at all. And then he could dispatch Hagrid and so on. I think The Scottish Book will have to answer that question. I'm gonna have to really go back through notes and either admit that I lost twenty four hours or I don't know, hurriedly come up with some back story to fill in. Either way, you either get to be right, or you get more story. So you can't complain.

[POTTERCAST - 12.23.07 - THE LEAKY CAULDRON]

Answer 2

Godric's Hollow had a number of Wizarding families living there, including Bathilda Bagshot and Dumbledore's own family house. In fact, Bagshot's A History of Magic mentions that Godric's Hollow is one of a number of villages where a relatively large number of wizarding families settled.

Given that Voldemort "almost destroyed" the entire house, and that Muggles arrived on the scene fairly quickly, it seems very likely that the attack was not quiet or unobtrusive. One of the other Wizarding families nearby most likely contacted Dumbledore as soon as they realized what was happening.

Answer 3

According to the Harry Potter Wiki the secret keeper for a Fidelius Charm is not necessarily the only person who knows the secret. The keeper can choose to reveal it, but the ones they reveal it to are prevented by the charm from passing it on to others. Is it possible that a number of the Potter's allies, including Dumbledore and possibly Hagrid, knew the secret?

Answer 4

Dumbledore had placed a charm on the house and immediately knew what had happened. He sent Hagrid to go get Harry.

(Source: JK Rowling's first interview on Pottercast Podcast)

Answer 5

This is purely supposition.

Since Hagrid shows up driving Sirius Black's motorcycle, he must have been in touch with Sirius before or upon arriving at the Potters' house.

Furthermore, by revealing the location of the house to Voldemort, Peter Pettigrew would not have broken the Fidelius Charm, but only instead made Voldemort a secondary secret-keeper. Thus the house would have remained undetectable to all other parties.

Pettigrew, upon learning of his master's death in the attack, was sent back to the house to retrieve Voldemort's wand. I assume these instructions came from Voldemort's disembodied soul. If Voldemort also intended to be the one to ultimately destroy Harry, then ironically Voldemort may have instructed Pettigrew to keep Harry alive until he could regain form and destroy him himself.

Pettigrew could have gone to the house and retrieved the wand. Then, in order to appear still true to the Fidelius, he could have contacted Sirius, claiming that he happened to arrive to an already destroyed house and needed help fetching Harry - making Sirius another secondary secret-keeper.

Sirius, seeing through the lie and becoming enraged at Pettigrew's betrayal, might have made Peter scared enough to just flee with the wand, leaving Sirius with the choice of pursuing him or tending to Harry.

At that point, Sirius notified Dumbledore (and Hagrid, directly or indirectly) to meet him in Godric's Hollow while he went off in pursuit of Pettigrew. Or, in removing Harry from the house to shelter him elsewhere, the house no longer was the home of any living Potter. That could have caused the charm to break, creating some undesirable attention that would have motivated Sirius to get help.

Either way, Hagrid showed up. And with Hagrid unable to apparate himself and Harry to the Dursley's, Sirius' flying bike would have been a natural choice for discreet travel, while Sirius took off in pursuit of Pettigrew.

Answer 6

Hagrid specifically confirms (in HP and the Cursed Child) that Dumbledore told him to go to Godric's Hollow and what had occurred.

Clearly he didn't know until he was told to go there by Dumbledore.

Hagrid: Oh. Oh. That’s not — that’s not — I weren’t — They told me, but — I were hoping for better . . .

He looks at them and bows his head. He mutters a few words, and then he takes some crumpled flowers from his deep pockets and lays them on the floor.

Hagrid [continued]: I’m sorry, they told me, he told me, Dumbledore told me, I can’t wait with yeh. Them Muggles are coming, yeh see, with their flashing blues and they won’t ’preciate a big lummox like me, would they?

As to how Dumbledore knew, DVK's excellent answer covers that one.

Answer 7

Mrs. Weasley glanced at the grandfather clock in the corner. Harry liked this clock. It was completely useless if you wanted to know the time, but otherwise very informative. It had nine golden hands, and each of them was engraved with one of the Weasley family’s names. There were no numerals around the face, but descriptions of where each family member might be. "Home," "school," and "work" were there, but there was also "traveling," "lost," "hospital," "prison," and, in the position where the number twelve would be on a normal clock, "mortal peril."
_{Goblet of Fire}

While it is unlikely for Dumbledore to have owned a similar clock that included "dead" and had hands for all members of the Order of the Phoenix, it shows us that, in general, it is possible to magically know the state of being of another person.

We can speculate that, since Dumbledore knew that both the Potters and the Longbottoms were implicated by the Prophecy, he used similar magic to keep a check on both families.

Answer 8

A bit of non-canonical speculation: That the Fidelius Charm only protects knowledge with a factual basis, and cannot protect something that is no longer true. Specifically, the Fidelius Charm can be used to guard the fact that the Potters live in such-and-such a place, but for only as long as they reside in any particular place. If they die, they no longer reside anywhere, and thus the spell ceases to protect them.

Now we toss in Dumbledore's sensitivity to magic, whereby he detects that he can now speak freely about the place, and he is able to tell that it's time to drop whatever it is he's doing and investigate.