Directed by Andrew Jarecki.

Three years ago, first time documentary director Andrew Jarecki started making a film about the top children's entertainer in New York, a clown called 'Silly Billy' aka David Friedman. But, early in the production, Jarecki discovered a disturbing secret which made him change focus from the man's clown act to the sex scandal that engulfed and destroyed his family in the late eighties. 'Capturing the Friedmans' is a compelling and emotional dissection of this tragedy, its antecedents and aftermath.

The Friedmans - teacher father Arnold, homemaker mother Elaine and three sons David, Seth and Jesse - were part of an affluent middle-class community in Long Island which became consumed by hysteria when Arnold and Jesse were accused of sexually abusing young boys during computer lessons at their house. David, who had just bought his first video camera, turned it on the family and recorded every bitter moment of them falling apart. This footage forms much of the emotional backbone of the film and is used alongside older family movies, shot during sunnier, more carefree times, and contemporary interviews conducted by Jarecki with many of the main protagonists.

On the eve of Thanksgiving 1987, federal police raided the Friedman home looking for child porn. They found a stack of magazines hidden behind Arnold's piano and they also found lists of children who had attended computer classes given by Arnold and Jesse, then aged 18, in the basement of the house. Worried that Arnold was molesting his students, Nassau County police started interviewing children who had attended these classes, uncovering - as they reported - numerous counts of abuse.

'Capturing the Friedmans' doles out bits and pieces of information in a teasing but often frustrating way. At first the investigation is portrayed as proceeding cautiously but before long Jarecki reveals the police pressurised children to admit they had been abused, the lack of physical evidence to support any accusations, incidents where children only 'remembered' the abuse under hypnosis and lies from a detective involved in the case. Each revelation makes the eventual outcome of the case - despite protesting their innocence, father and son both pleaded guilty and were imprisoned - all the more problematic.

But Arnold and Jesse's guilt or innocence is not the whole story here. 'Capturing the Friedmans' is a career making film for Jarecki, who has carefully marketed it on this ambiguity, a move which may perhaps be morally irresponsible but also gives the case against the prosecution - make up your own mind - a weight that a simple black/white summary of facts might not.

It makes for uncomfortable yet riveting viewing, particularly when the family starts to turn on itself. The four men band together, refusing to believe that anything could have happened, while Elaine is ostracised by her sons for her disloyalty towards her husband. And David captures it all. There's even a section where he, visibly distressed, addresses the camera - and the viewer: "This is private and if you're not me you really shouldn't be watching this." So why film it? The Friedmans always seem to have had a Super 8 camera to hand. Where other families might have had letters, photos and postcards, the Friedmans had decades worth of home movies - Arnold and Elaine as a happy young couple, children's birthdays, holidays, Passover feasts - all the nostalgic records of a family growing up. David's material shows the darkness coming in and Jarecki makes full use of it.

Although the version of events offered by Jarecki is deliberately inconclusive, 'Capturing the Friedmans' is still a brilliant film, a wonderful piece of investigative journalism and a stark study of the disintegration of a family faced with a nightmarish situation. It may also help Jesse Friedman. Now released after spending 13 years in prison, he has filed a motion to overturn his conviction, based on material uncovered by the filmmakers.

Caroline Hennessy