Holly Golightly wrote:What makes you think that Gower?
Because in the fourth book when they are all in the graveyard, Voldemort is talking to his death eaters. When he goes up the row of death eaters, he finds three empty spaces. He says that of these three, one is dead, one has fled from him(karkaroff) and one has left him forever. I presume that the death eater who has left him forever is snape.