Shuumatsu no Izetta: The Last Witch

[Kraco]

I don't think he said anything. There's no point in killing him otherwise if he's already spilled the beans.

Of course there's a point. The first point is that a man who gladly leaks military secrets of the highest order once is likely to do it again. The second reason is that I can imagine the intelligence dude somehow using this as propaganda or just to affect Izetta (he'd undoubtly say the spy killed the poor soldier, not that he himself did it).