"BOKOR"

In this site there is information on zombies and how some people truly believe that they exist. In different parts of the world such as West Africa and Haiti- where they are called "bokor,"they do not call them zombies but they have the same concept about how the dead can come back as "mindless slaves." There are even researchers that have tried to investigate whether zombies truly exist or not but do not have solid evidence to prove there are any.
Different stories about how people have encountered zombies and ways that they function are all in this interesting page, just take a look. "They are not self-aware and are not particularly dangerous unless fed salt, which restores their senses."