Halacha & Torture

How does halacha view torture? We can't torture animals, so perhaps kal vachomer people. On the other hand, what about "ticking time bombs"? How does pikuach nefesh apply, if it does?

Would it matter if it was physical or psychological? No beatings but yes sleep deprivation? Disorient but do not touch?

Any mekoros, thoughts, or views, are greatly appreciated.