The first episode of Children of Crime (BBC1) was accompanied by an uncanny echo - a dead three-year-old found on a railway line, and children in custody being interviewed about the event. At the time of writing the BBC had decided to go ahead with transmission of their programme about the Bulger case, but the matter must have given someone pause for considerable thought. Even if the cases turn out to be utterly different in their details, the incidental parallels are uncomfortably close - from the harsh bed of clinker on which both bodies were found to the uninvited mental picture of the dead boy's last walk. We now know what it looks like for an infant to be led to its death by a child and, in such circumstances, the knowledge is bound to leak from its container.

Such an unhappy accident of timing isn't a director's fault, naturally, but the programme still has to live with the consequences. And, in the light of a current mystery, the failure of Denys Blakeway's film to offer any new perceptions about that notorious antecedent was even more frustrating. The title - "A Riddle Wrapped Inside an Enigma" - couldn't help but make an implicit promise of unwrapping - that distance might have delivered some fresh perspective on the crime. But what you got here, dressed in the borrowed pomp of plangent counter tenors and low sostenuto (see Silent Witness or Millenium for recent fictional employments of the same devices) was a straightforward rehearsal of the dismal facts. Once again we had the regrets of witnesses who didn't intervene, the sombre testimony of policemen, the smudged photographs of two small boys on the brink of becoming symptoms of moral disease.

Some sharp details floated in this backwash from that first wave of coverage: a policeman recalled getting to his knees as he explained to Robert Thompson that he was going to arrest him, a dreadful combination of avuncularity and retribution; there was video footage of Thompson at a party, taken six months before the crime was committed and showing the sort of crop- haired, awkward child who automatically arouses protective instincts; there was a tape recording of Jon Venables' unbroken voice, gabbling a panicked denial in a police cell, as if he'd been caught stealing sweets from the corner shop. But the film did not move a step further in the direction of explanation, detailing the killers' backgrounds in the sketchiest way and even including a policeman's view that the two children were just "evil by nature", a kind of hopeless shrug of the shoulders in the face of the awful facts. It isn't that one expects any documentary to be able to offer a simple solution to such a conundrum, but some kind of attempt should be the lowest price of admission to such subject matter.

Not that it's easy to take a more ambitious route. The risk of novelty had been demonstrated the night before in Roger Graef's film for Witness (C4) about a social work experiment in which families are given responsibility for addressing their own problems. "Keeping It In The Family" followed the case of James, a troubled, underachieving, disruptive boy who shared the dysfunctional pedigree of James Bulger's killers. Instead of simply processing him through the care system, Wiltshire social services had convened a rolling conference (complete with beer and sandwiches) in which the members of his bafflingly extended family tried to come up with some plan of action (the alarming pony-tailed patriarch with a cross tattooed on his forehead turned out to be his step-grandfather). The programme was exasperating, repetitive, sometimes dull and finally inconclusive - a faithful account, in other words, of how such cases actually unwind in the world. But it was also poignant and ultimately far more revealing than last night's film about how readily the children we hurt for can turn into children we want to hurt. James's transparent need for some kind of dependable love made you ache - particularly in a scene in which he tried to make peace with his equally troubled father and was clumsily rebuffed - but it was all too easy to imagine him in circumstances where a policeman or a judge could talk confidently about his "evil nature" and not fear any contradiction.