Nickos 
It makes no difference he was the last person to see his family anyway, despite the invention of a phone call...or stumbling across the crime scene. The house was locked up. The rifle was in place. Jeremy turned up for work at 8am other farm hands turned up earlier...it was the height of the season gathering rape...
I suppose its a matter of opinion a, guessing game...sadly!

Hi Patti,

Now I beg to differ

, I believe one of the first suspects in a murder case is the last person to see the victims alive.
As for the "house was locked up" and "the rifle was in place" – I don’t follow?
The prosecution still convicted JB on the basis that all door widows were locked from the inside (and JB was sat outside with EP from c.4am - having killed them all earlier.)
JB could have been let in, or got in through a (larger and previously left ajar) window.
Pure speculation, but JB may have had a key copied and unlocked a door. In this case he could have removed a key from a locked door prior to leaving whf (Nevill checks the door before retiring - its locked so leaves it). JB returns, picks up the Anschutz from an outbuilding with one magazine fitted and two spare. He unlocks a door using the copied key, enters whf, locks the door and inserts the original key in the lock . JB carries out the killings. JB leaves – how, I don’t know, but 10 of the Jury were okay with this.
The window JB is supposed to have left by (with the knock it, drop down catch - as previously used by JB) must have been believable to the 10 Jury members - and one can understand why if JB had used this method to enter and exit whf before and, I believe at least on one occasion, after the murders.
JB, imo, admitted to entering whf this way as a cover for any evidence he may have left on the window that night - similar cover to the handling of the rifle the evening before the murders.