Mrs Figg

'''Mrs Figg is a witch who lives nextdoor to the Dursley family. She is asked to keep an eye on Harry when he is on his summer holidays off Dumbledore. As soon as she saw the sky turn cloudy and dull she ran over to the park where she watched Harry going to and witnessed the Dementor attack on Harry and Dudley.'''

Appearances
Harry Potter and the Order of the Phoenix