I can see why the makers are contrasting Wilkins relationship with his son and that of John Cooper.
Wilkins tries to be a good dad despite his work. Cooper abused his son Andrew, seriously injuring his back when Andrew was 12 years old. When Cooper wins a lot of money on the Spot the Ball competition. He does not take his son to Spain for a holiday.
When Cooper is interviewed by the police, when the pressure is on, he blames his son. Trying to set Andrew up as a murderer.
Wilkins finally makes a link to Cooper's appearance in the quiz show Bullseye. They finally get an idea of what he looked like in 1989.
Another brisk episode, even taking time out to explain the different types of forensic evidence to the audience.
One thing that is absent although briefly noted in this episode. Cooper was a suspect at the time of the original murders.
There were some allegations that the local police were incompetent. A junior detective too readily believed Cooper's alibi. The criticism against the police is nowhere to be seen at the moment.