No idea except i assume it was part of the Africa religions that came to the New World with the slaves and became interwoven with Catholicism.
I got curious and looked it up: zombie (n.) <br />
1871, of West African origin (cf. Kikongo zumbi "fetish;" Kimbundu nzambi "god"), originally the name of a snake god, later with meaning "reanimated corpse" in voodoo cult. But perhaps also from Louisiana creole word meaning "phantom, ghost," from Sp. sombra "shade, ghost." Sense "slow-witted person" is recorded from 1936.
I guess we have our answer.
It's an island term. Jamaica or Haiti or the Dominican Republic or somewhere. A long time ago there used to be medicine men (probably still around somewhere) who were able to turn living people into slaves by putting them into some kind of trance-like state. They would work all day long and exist on very little, and could not or would not speak. The term for these people became "zombi". I don't know what the term means though.
Because a young child looked at their dad's open coffin and said "zommmmmbie"
It's from "Zombi" which has some voodoo history or something... I forget the details.