Ch 19 pt 3

This had worked even better than he had hoped. Her outrage had focused everyone's attention on her. No one had noticed him augmenting her magic with his own as they hurried down the corridors behind her, filling her with the raw power she needed to do what she could never have done on her own. Pumping magic into her so that it bled out in visible waves around her as she hurried to the Headmaster's office. The other two Weasleys, wrapped up in their own concerns, didn't notice the colourless beam of energy he kept on her back as they ran behind her.

Even a pensieve memory wouldn't reveal his meddling, as it all took place outside the Headmaster's office.

Fortunately, Bozo managed to capture the event for posterity. No one could accuse Molly of killing a Wizard with her wand. And when, subsequently, the Aurors confirmed she was incapable of wandless magic, they wrote it off as a massive burst of accidental magic brought about by stress of the situation. A mother's love, after all, was a very powerful force, indeed. And no court, especially a Wizarding Court, would convict her, a Pure-blood, of killing a Half-blood, especially considering the circumstances.