  We demonstrate that the fermions in Reissner-Nordstr\"{o}m-anti-de Sitter
black hole background in the chiral limit $m=0$, are related to an $N=4$
extended one dimensional supersymmetry with non-trivial topological charges. We
also show that the $N=4$ extended supersymmetry is unbroken and we extend the
two $N=2$ one dimensional supersymmetries that the system also possess, to have
a trivial central charge. The implications of the trivial central charge on the
Witten index are also discussed.
