Ezra 5:5-6

But the eye of their God was on the elders of the Jews, so they [Tattenai and the others] did not stop them until a report could come before Darius, and then an answer was returned by letter concerning it. This is a copy of the letter that Tattenai, governor of the province west of the [Euphrates] River, and Shethar-bozenai and his associates, the officials who were west of the River, sent to Darius the king.