on account of

The prosecution to be removed under the section must have been instituted 'on account of' acts done by the defendant as a federal officer under color of his office or of the revenue or prohibition law. There must be causal connection between what the officer has done under asserted official authority and the state prosecution. It must appear that the prosecution of him for whatever offense has arisen out of the acts done by him under color of federal authority and in enforcement of federal law, and he must by direct averment exclude the possibility that it was based on acts or conduct of his, not justified by his federal duty. But the statute does not require that the prosecution must be for the very acts which the officer admits to have been done by him under federal authority. It is enough that his acts or his presence at the place in performance of his official duty constitute the basis, though mistaken or false, of the state prosecution.