The War of Saltes
As in “Essential Saltes:” turns out that HP Lovecraft had access to something resembling legitimate occult knowledge, although he certainly shaded stuff a bit. For example: Deep Ones? Not actually awful, once you get past the fact that they have no recognizable body language or facial cues. Ghouls, likewise, although you can generally get a decent enough psychological read on them. And shoggoths burn just fine.
But I digress. Yes, in fact there is a spell that, if cast on Saltes made from an intact corpse, will resurrect that corpse. Sort of. The revenant has no will of his or her own, lacks a personality, and cannot perform more than the simplest of tasks: but it can talk, and will answer factual questions to the best of its ability.
And that’s why so few Cold War spies got buried publicly, or at all. The Soviets routinely cremated their operatives and later scattered the dust; the West preferred to switch coffins and keep the remains on grisly file, as it were (usually at the bottom of nuclear silos, on the principle that if anybody could get in there then the country had other, more pressing problems anyway). Other countries made their own arrangements. Very unforgiving arrangements. But, of course, that was all in regard to spies who died at home, in bed. The unclaimed corpses of spies that died in the field were valuable commodities, particularly when nobody knew yet that the spies were dead.
The ‘War of Saltes’ that inevitably resulted was and is a grimly serious exercise, played by every nation-state in the world (including the Vatican and the United Nations); about the only grace point in it is that its participants have a practical rule about not actually killing each other. It’s not that the players respect the sanctity of life so much as they collectively realize that every new corpse that gets generated is another corpse that somebody will eventually have to spirit away from the battlefield. Smuggling corpses is already one of those difficult and awkward jobs; why add more work?
This would make torture somewhat pointless. If the captors in question are ethically loose enough to torture prisoners for information, then they’re probably also willing to shoot those same prisoners and then ask the resulting corpse the exact same questions. Torture would only be used in those cases where a living prisoner was seen as potentially more valuable than any information that might be gained from the corpse.
Yup. Or if people know that you grabbed somebody, of course.