Whom did Dumbledore kill?

[melhersheybar]

No: HPFGUIDX 176716

In King's Cross, when Harry and DD are talking about the difference 
between Hallows and Horcruxes, Harry tries to reassure DD that he is 
better than Voldemort because he wanted "Hallows, not Horcruxes", and 
he never killed anyone if he didn't have to in his quest for 
immortality, the greater good, etc.  I have been wracking my brain and 
going through the books, but I have not found any evidence that DD 
ever killed anyone (Arianna excepted).  I had always assumed he had 
killed Grindelwald, but once it was revealed that Grindelwald was 
still alive, I have no other ideas.  Is this just a reference to the 
fact that DD must have killed a Death Eater or two or some other dark 
Wizard in the course of his life or am I missing something.

Mel