First off, I developed this theory while listening to an episode of MuggleCast. I’ve come up with several theories over the course of the series, but I have never been convinced of one being more accurate than this one. I'm not quite sure why, but everything just seems to fit. Anyway, the theory that I’m about to discuss will answer many questions:
1.Who else was at Godric’s Hollow the night Lily and James died?
2.Why did Dumbledore need James’ invisibility cloak?
3.Why does Dumbledore trusts Snape?
4.Why was the Potter’s home destroyed?
5.Where was baby Harry from the time his parents died to the time Hagrid picked him up?
This theory begins with Snape’s overhearing of the prophecy. At this time he was still dedicated to Voldemort. We know that Snape runs off and tells Voldemort what he knows of the prophecy only to regret it later. It is when Snape learns of Voldemort’s plot to kill the Potter’s that he turns to Dumbledore. Snape tells Dumbledore that he will do anything to gain his trust, and so Dumbledore puts him to the test. Dumbledore knows that the Potter’s had a secret keeper; he just doesn’t know who it is. His mission for Snape is to follow Voldemort closely, making sure that no one gives up the Potter’s whereabouts. He tells Snape to closely watch Pettigrew, Black, and Lupin because they are the most likely choices for the Potter’s secret keeper.
Dumbledore tells James of Snape’s new allegiance and after much persuasion James trusts Dumbledore and thus, Snape. He offers his cloak to Dumbledore so Snape can then use it to tail Pettigrew, Black, Lupin, or Voldemort when necessary. For safety reasons and because of his reservations about Snape, James refuses to give up the identity of their secret keeper.
As Snape begins to use the invisibility cloak to track Voldemort, Lupin, Pettigrew, and Black, he overhears Wormtail giving up the location of the Potter’s to Voldemort. He immediately sets off to tell Dumbledore, but is unable to find him. He then leaves the cloak in Dumbledore’s office as a sign to the headmaster. He then sets off to Godric’s Hollow (remember, he overheard Wormtail telling Voldemort), only to find that the Potter’s have already been murdered. Snape then sets off through the house where he finds baby Harry. Snape gets Harry to safety, and then casts a spell to destroy the house and break the Fidelius Charm. He leaves Harry in the wreckage and immediately contacts Dumbledore (through owl post? I haven’t worked this out yet), alerting him of the events.
Because the Fidelius Charm is broken, anyone can find the house. Snape quickly goes back to his role as Death Eater and Dumbledore sends Hagrid to retrieve baby Harry. Here are the answers to our questions:
1.Who else was at Godric’s Hollow the night Lily and James died? Severus Snape (and possibly Wormtail)
2.Why did Dumbledore need James’ invisibility cloak? So Snape could alert him if the Secret Keeper betrayed the Potter’s
3.Why does Dumbledore trusts Snape? Because Snape saved Harry and broke the Fidelius Charm on the house
4.Why was the Potter’s home destroyed? Snape destroyed it to break the Fidelius Charm
5.Where was baby Harry from the time his parents died to the time Hagrid picked him up? He was rescued by Snape and then placed back in the wreckage until Hagrid returned. (Snape may have watched from afar to make sure Harry was safe)
Well, that’s my theory. I realize that I’m making several assumptions, but I guess you have to do that a little when formulating a theory. Even if I am wrong, I believe that it has to be something similar to this. With Jo having so much to tie up, it seems like it would have to be something that will answer a lot of our questions, while revealing just a few details and explanations. Let me know what you think!