The official police report into the deaths at Ffynnon Samson is the most details account of the scene, and the events which took place.
But that report, completed in 1977, led to a conclusion that it was Griff who was ultimately responsible. A claim the community rejects.
Now, in this episode, that report is held up to the light, as the locals ask where the evidence was which led police to that conclusion. Is there a smoking gun hidden amongst the statements and observations? Or does the report leave them with more questions than answers.
The episode hears from acclaimed forensic psychologist Prof David Canter, who reveals his own misgivings about the report, and his own theories on what may have taken place.
]
#Produced by What's The Story for BBC Wales