  We present the numerical investigation of the fermionic two-body decays of
tau sleptons $\tilde \tau_{1,2}$ and $\tau$ sneutrino in the Minimal
Supersymmetric Standard Model with complex parameters. In the analysis we
particularly take into account the cosmological bounds imposed by WMAP data. We
plot the CP-phase dependences for each fermionic two-body channel of $\tilde
\tau_{1,2}$ and $\tau$ sneutrino and speculate about the branching ratios and
total (two-body) decay widths. We find that the phase dependences of the decay
widths of the third family sleptons are quite significant which can provide
viable probes of additional CP sources. We also draw attention to the
polarization of the final-state tau in the $ \tilde \tau_{1,2}$ decays.
