However,,reading about interviewing suspects and their behaviour under interrogation is quite interesting,,and unless Jeremy is a raving psychopath,,then he's clearly innocent.
As according to the interviews,,those who are innocent feel confident that an investigation will clear them ( as in Jeremys' case,though it didn't unfortunately happen ) Also Jeremys' answers were direct without being evasive.
A guilty person will try and divert the interviewer from the questions in hand. So far as we know,,Jeremy answered all questions put to him,,arrogantly,,so we're told,,,but arrogance is usually confidence.
Use of some words during interrogation can be an indicator of guilt or innocence. If the word ( pronoun ) " I " is used,as opposed to " the " and " it ",,then usually a suspect is guilty. The other words are an indication that he isn't taking ownership. In other words---------innocent.
It's quite clear to me that psychology wasn't used in the interviewing/interrogation of Jeremy.