I'm quite serious when I say torture, it's as much punitive as it is deterrence, both of which are irrelevant to conducting an investigation and gathering evide

I'm quite serious when I say torture, it's as much punitive as it is deterrence, both of which are irrelevant to conducting an investigation and gathering evidence of wrong-doing. It's not practical because it's impossible to deny polygraph test results, so law enforcement officers have no incentive to be truthful about the results.