Vodou belief does not acknowledge death in the sense that is understood in the West: there is no death only transformation. The zombie is a being denied this transformation and trapped in a world it ought to have left. The zombie is not a soul in purgatory, as Christian belief would see it, because it does not by definition have a soul and also because it is not actually dead. It is rather a being trapped in a state without identity and denied the right to a means of life that is rightfully his own.
Richardson, M. and Fijałkowski, K., 1996. Refusal Of The Shadow. London: Verso.