Leading article: The usual suspects

He was a man of no fixed abode; a pathological liar who shared a blood type with the killer. He was known to the police, having been a prolific burglar who was placed in a borstal aged 11. Sean Hodgson was one of the "usual suspects" certainly, but he was also innocent. And yesterday he was set free having spent the past 27 years languishing in prison for the rape and murder of a barmaid, Teresa de Simone, in 1979.

At the heart of the case were two crucial pieces of evidence: that Mr Hodgson had confessed to the crime, and that he shared blood group A or AB with a sample taken from the scene. That one-third of the population shared this blood group, and that Mr Hodgson had confessed to dozens of other crimes – including some that had never been committed – was discounted. It was only when, decades later, DNA testing proved that the blood was not his that the conviction was finally quashed.

That a man can remain incarcerated for so long on the basis of such limited evidence reflects poorly on the standard of criminal prosecution in the 1980s for sure. But the injustices suffered by Mr Hodgson did not end there. His case has exposed weaknesses in other agencies – not least among them the Forensic Science Service which told Mr Hodgson's lawyers in 1998 that there was no DNA material on file to examine, delaying, as we now know, his release by 11 years.

One clue which could have suggested Mr Hodgson's innocence was his consistent refusal to accept parole, as to do so would require him to admit guilt. That he chose, as others still do, to lengthen his stay in prison, rather than confess to a crime for which he had already been convicted, speaks volumes about his predicament.

Soon he will be compensated for his ordeal though, absurdly, the cost of "board" in prison will be deducted from the final sum. While that payment will mark the end of his relationship with criminal justice, there are surely others who have lost their freedom on the basis of limited and misleading evidence. The Criminal Cases Review Commission has urgently called for DNA analysis to be undertaken in scores of other murder convictions. They should start with those of prisoners who refuse parole.