It seems to me that Harry Potter has already had in his possession the Horcrux that he and Dumbledore sought during Year Six.
- The parchment wedged into the substitute locket that they retrieved while on their excursion contained the note, “To the Dark Lord. I know I will be dead long before you read this… R.A.B.” The rest of the text is irrelevant, but the addressing of the note to the Dark Lord indicates that most likely a Death Eater was the one to steal the real locket since it is almost always only Death Eaters who refer to Voldemort as the Dark Lord.
- The Death Eater who stole the real Horcrux was backing out of service to Voldemort, and — thanks to the note — we know that person had the initials R.A.B.
- The only name mentioned in the first six books that conceivably matches the three now-infamous initials belongs to a Regulus Black. No middle name is yet known for Regulus.
- Regulus, Sirius Black’s brother, was a member of the Death Eaters who died around the time of Harry Potter’s birth.
“He was murdered by Voldemort. Or on Voldemort’s orders, more likely… From what I found out after he died, he got in so far, than panicked about what we was being asked to do and tried to back out. Well, you don’t just hand in your resignation to Voldemort. It’s a lifetime of service or death.” — Sirius Black
- Among the objects that George, Harry, and Sirius found when cleaning out the glass cabinets in the drawing room of Number Twelve, Grimmauld Place was “a heavy locket that none of them could open”.
- In the Dutch translation of the novel, Regulus Black is called Regulus Zwarts and the initials on the note are R.A.Z. In the Norwegian edition, Regulus Black is referred to as Regulus Svaart, and the initials R.A.S. are in the note. The same initials are in the German edition where Regulus’ last name is Schwartz. And in the Finnish translation, Regulus is Regulus Musta, and the note initials are R.A.M.
Book Seven proved my theory entirely correct! I love it when I’m right!