Matthew Poole and continuators on Acts 25:4

4 But Festus answered, that Paul should be kept at Cesarea, and that he himself would depart shortly thither.

It is most probable, that Festus had been informed by Felix of the Iews Malice against Paul: For Felix having been accused by the Iews unto the Emperor, might be supposed to have recriminated wheresoever he had any opportunity: And in all the time of his Government they were not guilty of a worse Fact than their design against Paul, it being Sedition, and intended Murder of one who had the priviledg of a Roman Citizen.

The Governors kept their Courts wheresoever they came.