Exactly, why would he leave a loaded rifle in reach of 2 young boys?
I don't think he did Lucy, it was all part of his pre planning, I don't think it was a spontaneous killing but pre planned, things would go wrong along the way, but Bamber new all along wiping his family out he would be a suspect, got to be, the only survivor would be a suspect, what better alibi than to let a third party find the bodies while your outside with the police, so the pre planning was before during and after? Just my take on it Lucy