  In this Letter we consider the problem of partial masslessness and unitarity
in (A)dS using gauge invariant description of massive high spin particles. We
show that for S = 2 and S = 3 cases such formalism allows one correctly
reproduce all known results. Then we construct a gauge invariant formulation
for massive particles of arbitrary integer spin s in arbitrary space-time
dimension d. For d = 4 our results confirm the conjecture made recently by
Deser and Waldron.
