  We consider the interacting system of D=4 N=1 supergravity and the
Brink-Schwarz massless superparticle as described by the sum of their
superfield actions, and derive the complete set of superfield equations of
motion for the coupled dynamical system. These include source terms given by
derivatives of a vector superfield current density with support on the
worldline. This current density is constructed from the spin 3/2 and spin 2
current density `prepotentials'. We analyze the gauge symmetry of the coupled
action and show that it is possible to fix the gauge in such a way that the
equations of motion reduce to those of the supergravity-bosonic particle
coupled system.
