Disordered Minds. Minette Walters

A thirty year old murder case and a possible wrongful conviction, Disordered Minds is the mystery thriller from crime queen Minette Walters.
In 1970, Harold Stamp, a retarded twenty-year-old was convicted on disputed evidence and a retracted confession of brutally murdering his grandmother – the one person who understood and protected him. Less than three years later he is dead, driven to suicide by isolation and despair. A fate befitting a murderer, perhaps, but what if he were innocent?
Thirty years on, Jonathan Hughes, an anthropologist specializing in social stereotyping, comes across the case by accident. He finds alarming disparities in the evidence and has little doubt that Stamp's conviction was a terrible miscarriage of justice. But how far is Hughes prepared to go in the search for justice? Is the forgotten story of one friendless young man compelling enough to make him leave his books and face his own demons?
And with what result? If Stamp didn't murder Grace Jeffries then somebody else did . . . and sleeping dogs are best left alone . . .