  In this paper we study fermion perturbations in four dimensional black holes
of string theory, obtained either from a non-extreme configuration of three
intersecting five-branes with a boost along the common string or from a
non-extreme intersecting system of two two-branes and two five-branes. The
Dirac equation for the massless neutrino field, after conformal re-scaling of
the metric, is written as a wave equation suitable to study the time evolution
of the perturbation. With the aid of Prony fitting of time-domain profile we
calculate the complex frequencies that dominate the quasinormal ringing stage,
and also determine this quantities by the semi-analytical sixth order WKB
method. We also find numerically the decay factor of fermion fields at very
late times, and show that the falloff is identical to those appeared for
massless fields in other four dimensional black hole spacetimes.
