Here is the thing. Lies are a tool and the interrogator needs to be skilful with this. Just like with a hammer you can fix or break something if you don't wield

Here is the thing. Lies are a tool and the interrogator needs to be skilful with this. Just like with a hammer you can fix or break something if you don't wield the tool correctly. When they lie, those statements are constructed to pull informations out that would otherwise be hidden. If the lie is constructed with leading facts it might end up lead into false confessions (thats bad). Investigator can include false info during the 'lie' to try to spot a false confession (covering for someone else, or even confusion and stress and wanting to get out of hostile environment). Bad investigator will lie and force a confession facts onto suspect. As already mentioned some people might crack under stress of the situation and go into fight or flight - 'get me out of here I will tell you anything' - because they were fed actual crime facts, suspect will use those to construct a confession that will look like a real thing. That practice is something people should get fired over.