F.B.I. Director Kash Patel said on Friday that agents had arrested a county judge in Milwaukee on charges of obstructing immigration enforcement.

The bureau arrested Judge Hannah Dugan on suspicion that she “intentionally misdirected federal agents away from” an immigrant being pursued by federal authorities, Mr. Patel wrote on social media.

The Trump administration has vowed to investigate and prosecute local officials who do not assist federal immigration enforcement efforts.

The case involves a frequent point of friction over immigration agents trying to arrest undocumented immigrants who are appearing in state court. Local authorities often chafe at such efforts, arguing they endanger public safety if people dealing with relatively minor legal issues feel it is unsafe to enter courthouses.

In the first Trump administration, a local Massachusetts judge was indicted by the Justice Department on charges of obstructing immigration authorities. The charges were dropped after the judge agreed to refer herself to potential judicial discipline.