One of the latest episodes in the war against ISIS was a raid by U.S forces that killed a leading figure and captured his wife. According to news stories, the intent was to capture Abu Sayyaf, believed to play a major role in financing ISIS via black market sales of oil, for the sake of valuable information he could provide about ISIS operations. Killing him, while better than nothing, was not the preferred outcome.
That raises an obvious question. Assuming the raiders had been successful, how did they expect to get at information in Abu Sayyaf's head? The most obvious conjecture is by torture—which the U.S. government claims not to engage in. An alternative possibility is by threatening his wife—also not, so far as I know, a tactic U.S. forces admit to using.
A central principle of economics is revealed preference. What people do provides more reliable information than what they say.