Fred West - "someone who had opted out of the human race, the epitome of evil", said the court. But made, or just born that way?
This programme, the first of a new series exploring the motivations of well-known serial killers, delved into the childhood of one of the country's most notorious.
Fred West's future was defined by his fateful meeting with Rosemary
Long before he made his infamous base at 25 Cromwell Street, Fred West had a rural upbringing, was someone "who was a survivor, who got by on his wits".
While there are plenty of people like that who lead decent, harmonious lives, the programme explored how West's raw sexuality - including incest at home - developed after his motorbike accident at the age of 17, when he suffered a head injury, and, as the profiler explained convincingly, the brakes were taken off his already psychopathic tendencies, and his first victims came into his sights.
It also documented his fateful meeting with Rosemary Letts, 12 years his junior and potentially his next prey, until their shared fantasies - what the psychologist called "interlocking pathology" - meant they became conspirators instead. Interestingly, it explored the theory that they later became competitors, as they sank to such depths of depravity that each feared they could actually be the other's next victim.
Two things of note came out of this programme. After faithfully charting the motivations of Fred and Rosemary as they ran their chamber of horrors at Cromwell Street - Fred's lack of revulsion, his need for approval from the mother figure of Rose - it finally addressed the leading question: born to kill?
The experts appeared to conclude that Fred West could not escape his genetics, that he was likely born with characteristics that would make it reasonably easy for him to turn into a killer, a path that was unavoidable once he encountered Rose.
Which seems clearly argued after an hour, until you suddenly think: well, what else can they say? That he was a really good bloke until... when exactly? The history of his extended killing spree - as one commentator observed, "he knew he'd had a good run" - appears to speak for itself.
The thing that stood out for me was the clear, dry-eyed account of Caroline Owens, once a runaway discovered by the Wests, recruited to be their nanny and later subjected to a horrific ordeal at their hands that made her "happier being dead".
She was still angry when she returned to the now transformed Cromwell Street - "they didn't take enough away" - and that West got to decide his own fate by hanging himself in his prison cell, but her demeanour, calmness and, hopefully, authentic assertiveness over her former tormentors represented at least one small triumph in this history of horror.