Almost a month after UBS executives faced a congressional grilling over the bank’s alleged attempts to circumvent U.S. tax laws, the Justice Department has brought the first charges against a client of the Swiss banking giant.

As part of the Justice Department’s attempt to determine the identities of UBS’s U.S. clients, federal prosecutors have charged Steven Rubinstein, an accountant in Boca Raton, Fla., with filing a false income tax return.