Is that from the Crimewatch reconstruction? I need to watch it again...Apologies if I have this wrong but I thought Brenda went to the door first time and by the time she got there they had gone. 40 minutes later they returned and that time Akan answered. One thing I found odd that as described is that it seems Alan went out the back door and around the side of the house. Why didn't he just open the front door? Was Alan being cautious or suspicious of something and trying to sneak a look to see who it was? Did he have something to be worried about ?
For some reason I thought it was much less than 40 minutes before they returned.