Booggie
I never liked dumbledore too much a control freak keeps secrets upon secrets and if you hear him say "For the greater good." someone is getting murdered or shafted in a very bad way, im pretty sure he used Snape to murder purebloods in his way such as Bones,killed off the Potters,clippled the blacks to extintion,killed the prewitt twins due to them chaffing at his rule so he had death eaters jump and kill them being snape is a double spy