In cases where people are just potential suspects, cops may try to determine if the suspect is lying or not but that's not the situation here. In these kinds of cases, the cops already have the logs which are considered sufficient evidence for the arrest.

For interrogations following an arrest, the process is not meant to determine if you are lying or not. It's meant to get that final piece of evidence that makes the case a slam dunk: your confession. So they make you feel uncomfortable, scared, and desperate to leave. Once they get you in that mind frame, they make it seem that the best way for you to get out of this scary situation is to start talking, and then steer you into the hope that you can just go home if you admit to the crime. This tactic even works on innocent people. Just check out the Innocence Project and you'll see plenty of cases where an innocent person ADMITTED IN WRITING to doing the crime after a long interview. Of course, once they came to their senses, they try to take it back but it's too late.

I'm glad somebody else mentioned swordfish. How about that "supercomputer" they let him use? I guess their IT guy decided buying a bunch of 15" LCDs was easier than figuring out how to switch to a reasonable os. Give him a raise.