Murderous Intent (2006)

Two sullen schoolboys have made a deadly deal, and it's up to muy photogenic forensic psychologist Toni Collette to get to the bottom of the mess in Murderous Intent (2006). Newcomer Eddie Redmayne is arrested on suspicion of polishing off a fellow pupil at his boys school, but Toni doesn't believe that he has what it takes to take out another teener. She digs into his world and discovers a complex, twisting tale that goes all the way back to the Crusades and ends in teen-on-teen terror. It seems that Eddie's creepy roomie, Tom Sturridge, was obsessed with the Knights Templar, reading about them whenever he wasn't pickling the corpses of little critters he'd cut down in the prime of life. Flashbacks track the evolution of the boys' bizarre pact, and the body count mounts as Toni mines the weird mind of her suspect. It's Silence of the Lambs (2001) in short pants!