Fifteen years ago, promising young footballer Kevin Nunes was shot dead on a country lane in Staffordshire. Five men were convicted of his killing, and jailed for life. But just four years later, their convictions were quashed, following concerns about the way police handled a key prosecution witness.

The Court of Appeal Judge said it appeared to be "a serious perversion of the course of justice," and an investigation was launched into misconduct claims against four of the UK's most senior officers.

Now, as the report into the police investigation is finally released, File on 4 speaks to those at the centre of the saga. Will the family of Kevin Nunes will ever get the justice they seek, and what does the case tell us about police transparency and accountability?

Reporter: Phil Mackie
Producer: Laura Harmes.