  We obtain a partial differential equation for a pulse travelling inside a
Bose-Einstein condensate under conditions of electromagnetically induced
transparency. The equation is valid for a weak probe pulse. We solve the
equation for the case of a three-level BEC in $\Lambda$ configuration with one
of its ground state spatial profiles initially constant. The solution
characterizes, in detail, the effect that the evolution of the condensate wave
function has on pulse propagation, including the process of stopping and
releasing it.
