The Defence Argued That David Killed Robin and Then Turned the Gun on Himself

Investigators ruled out the first scenario that David killed everyone and then went to work. Robin's body was still warm to the touch when police arrived at the scene. So he couldn't have been killed more than an hour before the police showed up. His body being found in the living room also meant that it was likely Robin had risen and had been up and about at the time of his death with the alarm set for 6.30am. That would mean he woke after David had gone out on his round and had been killed when David got back. The defence however argued that David did indeed wake as usual at 5.30am and he left the house 15 minutes later, then at 6.