[HBP] Why didn't Voldemort Modify Hagrid's Memory?

[pippin_999]

No: HPFGUIDX 190183

Cassie:
> I was just listening to HBP (The Stephen Fry Ver.). Voldemort modified
> Morphin's memory to make him think he had killed the Riddles and Hokey the
> House Elf to make her think she had killed Hephzibah Smith, but didn't
> modify Hagrid's memory to make him think he had set Aragog on the
> muggle-borns/opened the chamber of secrets.
> 
> Any thoughts as to why?
>

Pippin:
There were multiple attacks, not just the one that killed Myrtle. That would require more extensive memory modification than was done on Morfin or the House Elf, and as we know, there's a limit to how much can be done without creating obvious damage. And while Riddle did want the knowledge of how to open the Chamber preserved, he didn't want it revealed to everyone. He wouldn't want that knowledge implanted in Hagrid and exposed to questioning.

Also, there was a possibility that if Hagrid thought Aragog was guilty, he would turn him in, and it would be immediately obvious to everyone, especially Myrtle, that this was not the creature with great big yellow eyes which attacked her.

Pippin