I think that when dealing with people who are planning acts that endanger a lot of danger and death to others and there is an element of time involved that puts the investigators under pressure to find out fast hwat is planned and who exactly is carrying on to organise these acts, you have several paths you can try:
- Pursue classic interrogations, maybe good cop/bad cop, isolatated cells
- Put the person under torture like 'waterboarding' (simulated drowning) and beating them up, etc
Consider that many of them are religious extremists who are kind of brainwashed for years and are really hard to brake up to talk, eager to give their life in the process of killing for their beliefs. And when the crime is being in the process of being further prepared, it is vital to prevent, say a bomb to be built, nuclear material to be bought, planes to be hijacked, I think we must accept the sad fact that the person is going to be abused beyond human rights.
But if a large number of other lifes might be saved, I am willing to accept that.