The Belle II experiment is one of the best environments to study tau physics since the SuperKEKB collider produces a large number of tau leptons. The last measurement of the "tau -> e e+e- nu nu" branching ratio by the CLEO Collaboration reports an uncertainty of about 53%. In this talk, we will show an update of the search for "tau -> l l'l' nu nu", where "l" could be either an electron or a muon. We expect to confirm the observation of "tau -> e e+e- nu nu" and report a first observation of "tau -> mu e+e- nu nu". Techniques developed in this analysis will be used for the search of charged lepton flavor violating (cLFV) decays "tau to l l' l''", where "l, l', and l''" could be either an electron or a muon. We will describe briefly the status of these searches.