Dina antaganden är korrekta. Dumbledore presenterade en föreställning om att mörda Narcissa.
Vid en tidpunkt under trollkriget började Death Eaters gå efter familjer. Dumbledores bror hölls i gisslan och torterades ihjäl under Cruciatus-förbannelsen. Som svar svarade Dumbledore "Narcissa".
"Do you also wish to see my brother as he died under the Cruciatus?" said Albus Dumbledore. "Voldemort sent me that memory as well!"
"And that - " Harry was having trouble producing a voice, for the growing sickness in his chest. "That was when -" The words seemed to burn in his throat, as the awful knowledge dawned on him, the horrible understanding. "That was when you burned Narcissa Malfoy alive in her own bedroom."
Albus Dumbledore's gaze was cold as he answered. "To that question only a fool would say yea or nay. What matters is that the Death Eaters believe I killed her, and that belief kept safe the families of all who served the Order of the Phoenix - until this day. Now do you understand what you have done? What you have done to your friends, Harry Potter, and to any that stand with you?" The old wizard seemed to grow still taller and more terrible, as his voice rose louder. "You have made them all targets, and targets they will remain! Until you prove, the only way it can be proven, that you are no longer willing to pay such prices!"
"And is it true?" Harry said. There was a buzzing sensation filling him, his body growing more distant. "What Draco said, that Narcissa Malfoy never got her hands dirty, that she was only Lucius's wife? She was an enabler, I get that, but I can't back that deserving being burned alive."
"Nothing less would have convinced them that I was done with hesitation." The old wizard's voice brooked no question and no refusal. "Always I was too reluctant to do as I must, always it was others who paid the cost of my mercy. So Alastor told me from the beginning, but I did not listen to him. You, I expect, shall prove better at such decisions than I." (Chapter 82)
På grund av Dumbledores svar såg Death Eaters att de inte hade något att vinna och mycket att förlora genom att fortsätta att gå efter andras familjer. Så stannade de. Därför gjorde Dumbledore det.
Det finns ingen indikation någon än Dumbledore vet att Narcissa lever, speciellt Lucius. Lucius var ett av de personer som Dumbledore var tvungen att sluta från att göra detta någonsin igen. Det skulle helt besegra Dumbledores syfte om Lucius visste.
Att Narcissa faktiskt räddades var förhuggad här, och när Harry träffade Dumbledore först.
"I didn't know about Fawkes," Harry's voice said rapidly, "so he told me that Fawkes was a phoenix, while he was pointing to a chicken on Fawkes's stand so I'd think that was Fawkes, and then he set the chicken on fire - and also he gave me this big rock and told me it had belonged to my father and I ought to carry it everywhere -" (Chapter 70)
Dumbledore beskriver det i hans brev till Harry som:
"Here's the last thing," Harry Potter said. "I found it in a folded parchment whose outside said that it was the last weapon to be used against House Malfoy, telling me not to read any further until the whole war hung in the balance. I didn't want to tell it to you before because I thought it might prejudice your decision unfairly. If you were a good person who never killed or lied, but you had to do one or the other, which would be worse?" (Chapter 120)
... som bekräftar för oss visste Lucius definitivt inte. Om Lucius blev redan utpressad, skulle det inte vara det "sista vapnet" att använda mot House Malfoy: det är en kanin du drar ur en hatt när det inte finns något kvar, vilket medför någon risk, för att Det visar att du aldrig var riktigt villig att återvända i naturen trots allt.