Dumbledore turns evil.

[MMMfanfic at hotmail.com]

No: HPFGUIDX 18479

Interesting, and a nice point about spy within Grindlewald's circle.  
There are some canon evidence supporting Dumbledore with a dark past:

1. PS/SS Chapter 1. Dumbledore remarked that Voldemort possesses 
power that he would never have and McGonagall replied, 'It's only 
because you're too noble to use them.'

2. CoS. In the History of Magic class, a student said Dumbledore 
can't open the Chamber of Secret because some sort of dark art is 
required and Prof. Binn retorted, 'Just because a wizard doesn't use 
dark magic doesn't mean he can't.'

3. Dumbledore loves to give people a second chance? Why? Is that 
because someone once gave him a second chance?

Dumbledore's character would certainly have more depth if he was once 
associated with the dark art.  For example, the scene in the 
Pensieve. Dumbledore, while defending Snape, said, 'He's now no more 
a Death eater than I am.'  If Dumbledore has any sort of past 
associations with the Dark arts, then this statement very poignant 
and now has an additional meaning -- 'Look at me, I turn from the 
dark side and I trust him to pull through as well.'