Adam,you could have saved yourself writing all that after your first sentence because if you think for one minute,,as MOST do,,that Jeremy " killed " everyone for the inheritance.
Jeremy might be an idiot for lots of reasons,,but I'm sure when it was alleged that he spread it about he " could,or was going to kill his family ",,that he'd thought about the inheritance side and would have realised that had he committed the crime,that he'd get not a cent anyway if he was caught. A criminal automatically forfeits all rights to an estate under those circumstances.
Though he wasn't exactly caught,as blamed for the crime,which comes under the same law once they're arrested and imprisoned,,so you can forget any money which he would have benefitted from,,,and it wouldn't have been the whole lot either. Neverthless,,Jeremys' thoughts would probably have been with his grannie,,who'd died the following year,1987,,and where her original will stated that Jeremy would have received a share of the farm,,,so why would he risk killing all his family for the sake of a sick old lady whose days were numbered ?