. . put 'em in long term storage, but with hope of getting out some day (maybe a hint of a deal). Bring each one in every so often for interrogation, but give them the idea they're in dry storage. Move 'em around a bit. Give them enough leash they think they can find a safe spot to talk. Make sure there is no safe spot. Let 'em have enough outside news so they want to talk about it, and what they'll do to us when they get out. Eventually someone's going to start bragging.