Two-year-old Keanu Williams, who was beaten to death by his mother, had 37 separate injuries, including extensive bruising to his head, stomach, back and legs, when he died.
The toddler also had a fractured skull and a fist-sized tear on his stomach when he was found dead in January 2011.
The detective in charge of the investigation said it was the "worst" child abuse case she had ever seen.
More top news
ITV News visits the county in the wake of the EU referendum result and finds increasing frustration with Britain's political leaders.
The schoolchildren rescued from the Brecon Beacons during a Duke of Edinburgh exercise were never missing, their headteacher has insisted.
"By killing his children, Mr Sheats will have to live the rest of his life with this horrible memory."