Shortly after the murders took place,,and after locks were changed and security installed,,Jeremy was offered a set of new keys to WHF. He declined the offer,instead handing them to AE !
Doesn't sound to me as if he'd murdered 5 people if he refused the " opportunity " to enter the farmhouse.
Didn't he want to re-trace his steps ?
Didn't he want to wipe the blood from the window-sill from which he allegedly got in and out of ?
Didn't he want to put the silencer in his pocket in which to dump across the swamps near to where he'd pedalled hell for leather in his wetsuit ?
Didn't he want to return for the watch of his fathers' ?
Didn't he want to pocket some of the jewellery that nobody would have known about ?
Didn't he want to look for the key to the safe to see what was in it ?
Didn't he want to rifle ( pun ) a few drawers and cupboards ?
Isn't this what greedy murderers do who make money their God ?
NO. Unbeknowns to Jeremy,,all that was done for him ! " Come into my parlour said the spider to the fly ".
Then poor Jeremy,,thinking that he had friends on his side giving him support,,,turned on him as quick as lightening. He,,knowing that relationships had been somewhat strained over the years between families,,was trying to build bridges,,and even gave AE a bunch of flowers for what he thought,,were for their acts of kindness towards him at that dreadful time of having nobody to fall back on.
Then the amateur sleuths got to work !