Observartion of. mu. 3. pi. events in e/sup +/e/sup -/ annihilation

We have observed events of the type ..mu../sup + -/ + (3..pi..)/sup + -/ in e/sup +/e/sup -/ interactions at center-of-mass energies above 6 GeV. The properties of the events are consistent with their coming from the heavy-lepton decays tau ..-->.. ..mu nu..nu-bar and tau-bar ..-->.. nu-bar3..pi.. or tau-bar ..-->.. nu-bar4..pi... The three-charged-pion invariant-mass distribution shows a significant peak at a mass 1.1 GeV/c/sup 2/. We find the branching ratio into three charged and any number of neutral pions B (tau/sup +/ ..-->.. nu-bar..pi../sup +/..pi../sup +/..pi../sup -/n..pi../sup 0/) = 0.18 +- 0.065.