  The formulation of the laws of black hole mechanics assumes the stability of
black holes under perturbations in accordance with the "cosmic censorship
hypothesis"(CCH). CCH prohibits the formation of a naked singularity by a
physical process from a regular black hole solution with an event horizon.
Earlier studies show that naked singularities can indeed be formed leading to
the violation of CCH if a near-extremal black hole is injected with massive
charged particles and the back reaction effects are neglected. We investigate
the validity of CCH by considering the infall of charged massless particles as
well as a charged null shell. We also discuss the issue of third law of black
hole mechanics in the presence of null charged particles by considering various
possibilities.
