Any chance the cops are playing the two (JM and RAT) against each other? Or is that just a tactic used in police movies. They could be telling JM "hey, RAT knows you're involved and is asking us to investigate YOU in the AM murder. Saying HE's innocent. He's throwing you under the bus." Maybe that cracked JM's shell. If he angers easily, he might not be able to control himself when he wants to defend himself and might spit out some useful info in one of his fits of rage. Maybe he blurted out something like "what? That (*$%$%! He knows damn well that HE's the one that killed her..." This gives the cops all they need to know - that JM was there and that JM knows what happened to AM.
Does that make sense? Rile up JM by bringing up his possible connection to RAT but bringing it up as if it's fact to make him think they have evidence to link him to the AM case and other murders.
Does that make sense? Rile up JM by bringing up his possible connection to RAT but bringing it up as if it's fact to make him think they have evidence to link him to the AM case and other murders.