Orchid Blue, By Eoin McNamee

How legitimate is it to plunder real-life crime as grist for a fiction writer's mill? And how long an interval should be left before picking over the bones of a murder? Celebrated crime novelists who have transmuted grim reality into uncompromising books include James Ellroy, who fictionally confronted his own mother's murder in The Black Dahlia; and David Peace, who controversially used the Yorkshire Ripper's reign of terror in the Red Riding Quartet. Eoin McNamee steps into this dangerous territory with Orchid Blue – less visceral than these predecessors, but equally provocative, as he deals with the last hanging on Irish soil.

The source of McNamee's dispassionate but disturbing novel is the case of Robert McGladdery, charged with the brutal murder of 19-year-old Pearl Gamble near Newry on a January night in 1961. On 22 September, McGladdery was hanged in Crumlin Road gaol. The judge in the case, Lancelot Curran, was the youngest attorney general at Stormont, centre of the Unionist establishment. Nine years earlier, Curran had been in the news when his own daughter Patricia, also 19, had been murdered, a case that McNamee examined in his 2002 Booker-nominated The Blue Tango. What was Curran's involvement in the murder of his daughter – and was an innocent man subsequently sent to the gallows?

A similar miscarriage of justice was rewritten in novel form by Laura Wilson in A Capital Crime, which focused on a calculating older man and a naive "sacrificial lamb" (John Christie and Timothy Evans). But McNamee's source material is less familiar than the Rillington Place murders, and he is able to fashion a genuinely unnerving fiction out of this once-notorious murder case.

His real skill, apart from his creation of a dark mélange of homicide and revenge, is to invent a dirt-digging protagonist, Detective Eddie McCrink. Hard-boiled and bloody-minded, McCrink has returned to Northern Ireland policing from London. Swiftly, in the teeth of official disapproval, he becomes convinced that powerful people are using the system for their own ends, and that the hapless McGladdery is unlikely to be given a fair hearing. The word of a judge – particularly in the 1960s – was law.

In Resurrection Man, McNamee detailed the bloodletting of the UVF gang the Shankill Butchers. If Orchid Blue lacks the cold fury of his earlier books, it is still harshly compelling.