A spy's message to his handler about troop movements is intercepted. The message is then changed to carry the false information that the infantry will be on the move without artillery support and sent onward. Did those who changed the message lie?
To lie, one must assert. But suppose the handler finds out about the change. Could she correctly say: "The counterintelligence operatives asserted to us that the infantry would be on the move without artillery support?" That just seems wrong. In fact, it seems similar to the oddity of attributing to an actor the speech of a character (though with the important difference that the actor does not typically speak to deceive). The point is easiest to see, perhaps, where there are first person pronouns. If part of the message says: "I will be at the old barn at 9 pm", it is surely false that the counterintelligence staff asserted they will be at the old barn (even though, quite possibly, they will--in order to capture the handler), but it also doesn't seem right to say that the counterintelligence staff asserted that the spy will be there.
The trust account of lying, defended by Jorge Garcia and others, seems to fit well with this judgment. On this account, to lie is to solicit trust while betraying it. But one can only betray a trust in oneself. The counterintelligence operatives, however, did not solicit the handler's trust in themselves: rather, they were relying on the handler's trust in the spy, and that trust the operatives cannot betray.
But there are some difficult edge cases. What if a counterintelligence operative dons a mask that makes him look just like the spy, and speaks falsehoods with a voice imitating the spy? But what if a spy goes to a foreign country with an entirely fictional identity? I am inclined to think that on the trust account the two cases are different. When one imitates the spy, one relies on the faith and credit that the spy has, and one isn't soliciting trust for oneself. When one dresses up as someone who doesn't exist, I think one is trying to gain faith and credit for oneself, and it seems one is lying. But I am not sure where the line is to be drawn.