  We study the possible covariant Lagrangians that describe the propagation of
pure spin-3/2 particles. We show that, apart from the well-known
Rarita-Schwinger Lagrangian, there is another possibility where the field is
described by a gamma-traceless combination and that both Lagrangians yield the
same physical predictions for the interaction of conserved sources. We also
prove that for the case when the spin-2 field is described by a traceless
field, there is no possible spin-3/2 action that makes the system
supersymmetric. Nevertheless, the interaction between this field andthe
spin-3/2 field may be possible.
