‘She was Imperiused and then Obliviated’ looks like the likeliest hypothesis right now.
I think the idea is that with just an Imperius and an Obliviation, she wouldn’t remember herself deciding to cast the Blood-Chilling charm—she might remember doing it, but not remember deciding to do it, which would be difference enough to be noted by the Veritaserum and/or Legimancer.
So you’d need the False-Memory-Charm on top of that, and once you have the False-Memory-Charm you don’t actually need to complicate this further with an Imperius and Obliviation, it suffices by itself.
If that were true, it’d be really easy to detect an Imperius by examining the subject’s memories… The subject wouldn’t remember deciding to do anything the Imperius made them do. [Test Foo]
Instead, McGonagall’s statement implies that the best way to figure out whether the subject was Imperiused is to see if they remember being Imperiused, even with all the information that would allow you to perform Test Foo.
Then again, McGonagall’s speaking outside her area of expertise.
If that were true, it’d be really easy to detect an Imperius by examining the subject’s memories...
Lucius is an Occlumens, and lesser Death Eaters might self-obliviate whole weeks/months of their lives and then claim that they were both Imperiused and obliviated.
Instead, McGonagall’s statement implies that the best way to figure out whether the subject was Imperiused is to see if they remember being Imperiused, even with all the information that would allow you to perform Test Foo.
I suppose that throughout the duration of Imperius its victim may be thinking to himself “Damn this Imperius which is making my body do things that I don’t want to do”, so one wouldn’t need to obliviate just the moment of the Imperius, but the whole sequence of events. Which would be counterproductive in Hermione’s case as her own memories is the chief incriminating factor.
I think the idea is that with just an Imperius and an Obliviation, she wouldn’t remember herself deciding to cast the Blood-Chilling charm—she might remember doing it, but not remember deciding to do it, which would be difference enough to be noted by the Veritaserum and/or Legimancer.
So you’d need the False-Memory-Charm on top of that, and once you have the False-Memory-Charm you don’t actually need to complicate this further with an Imperius and Obliviation, it suffices by itself.
If that were true, it’d be really easy to detect an Imperius by examining the subject’s memories… The subject wouldn’t remember deciding to do anything the Imperius made them do. [Test Foo]
Instead, McGonagall’s statement implies that the best way to figure out whether the subject was Imperiused is to see if they remember being Imperiused, even with all the information that would allow you to perform Test Foo.
Then again, McGonagall’s speaking outside her area of expertise.
Lucius is an Occlumens, and lesser Death Eaters might self-obliviate whole weeks/months of their lives and then claim that they were both Imperiused and obliviated.
I suppose that throughout the duration of Imperius its victim may be thinking to himself “Damn this Imperius which is making my body do things that I don’t want to do”, so one wouldn’t need to obliviate just the moment of the Imperius, but the whole sequence of events. Which would be counterproductive in Hermione’s case as her own memories is the chief incriminating factor.