  We have shown analytically that radiation from a collapsing shell which leads
to a charged black hole, whose exterior is described by the RN
(Reissner-Nordstr\"om) metric (and hence the background spacetime is
non-globally hyperbolic), is processed with a unitary evolution. For the
analysis, we have used the Wheeler-deWitt formalism which in turn gave rise to
a Schr\"{o}dinger-like wave equation. We showed the existence of unitarity by
proving that the trace of the squared density matrix of the outgoing radiation,
from a quantized massless scalar field, is unity and that the conservation of
probability holds for the wave function of the system.
