> No, a dangerous serial killer is one regardless of conviction. True enough, but the point he raises is at what point do you justify illegal actions. In your

> No, a dangerous serial killer is one regardless of conviction. True enough, but the point he raises is at what point do you justify illegal actions. In your example, torture may or not bear fruit, depending on if your suppositions are correct. The point is generally that in order for extreme measures to be taken, extreme justification must be given. And in general the justifications needed for torture would be so high that you would probably be able to convict without it, i.e. You can only torture someone if you knew beyond any doubt they dunnit. The point of restricting the collection of evidence is to ensure that law enforcement go through a process with justification at each stage. This is to protect innocent/law abiding from law enforcement itself, as a lot of the acts they go through in the course of their business would be illegal if they were not law enforcement.