  We present a search for top-antitop events with a tau lepton in the final
state. The data sample corresponds to an integrated luminosity of 194/pb
collected with the CDF II detector from proton-antiproton collisions at a
center of mass energy of 1.96 TeV. We observe two events with an expected
signal of 1.0+/-0.2 events and a background of 1.3+/-0.3 events. We determine a
95% confidence level upper limit on r_tau, the ratio of the measured rate of
top->tau nu quark to the expectation, of 5.2.
