  Selectron decays constitute a source of 100% polarised neutralinos, whose
helicity is fixed by the charge and "chirality" of the decaying selectron. In
SUSY scenarios where the second neutralino X_2^0 has three-body decays, the
cascade decay e_L -> e X_2^0 -> e X_1^0 mu+ mu- provides a clean place to study
CP violation in the neutralino sector, through the analysis of CP-violating
asymmetries involving the X_2^0 spin s and the momenta of the muons. We show
that a CP-violating asymmetry in the triple product s . (p_mu- x p_mu+) could
be observable at a 800 GeV linear collider provided the gaugino mass M_1 has a
large phase at the electroweak scale. We compare our results with X_1^0 X_2^0
production, where a CP asymmetry is also observable within these scenarios.
