Conspicuous by its absence in James Robertson's fifth novel is any mention of Lockerbie.

This may strike some readers as odd because The Professor Of Truth is also concerned with the bombing of a plane bound for New York which falls from the sky onto a small Scottish town killing hundreds of people, including the wife and daughter of its narrator.

The omission is of course deliberate, for Robertson is a novelist and not an investigative reporter. As such he inhabits a world where concepts such as truth and justice and retribution require more subtle coloration than that offered by black and white. Nevertheless he has chosen as his protagonist a man who needs desperately to get to the bottom of things for his own peace of mind.

It's what is routinely described as closure, which others who have lost loved ones are often inclined to embrace even when they suspect the evidence is inadequate or planted. Alan Tealing, however, does not believe that Khahil Khazar, the man convicted of planting the bomb which killed Emily and Alice, is guilty. Hence his obsession with what he calls "The Case".

Alan is a lecturer in English Literature at a university which bears glib comparison to Stirling. He is – as he is at pains to stress – not really a professor. Rather he is "the PhD kind of doctor" and would otherwise have been content to melt into the crowd. But what makes him special, what makes him unusual, are the deaths of his wife and daughter. Thus where others of his ilk might inspire disdain, he receives "a hushed kind of reverence".

As Robertson demonstrated most recently in And The Land Lay Still, he is adept at creating and empathising with characters who are in some way damaged and having difficulty in coping with the hand they've been dealt. As a narrator Alan is equipped to tell a story, which is important. But the way he expresses himself, the language he uses, is that of a man used to conveying information in an academic manner. He is not expressive, nor is he a natural user of metaphor or simile. That, too, is deliberate, and highly effective.

In essence, he thinks like a teacher of literature, not a writer. Towards the end of the novel, Alan at last comes face to face with Martin Parroulet, the man whose testimony led to Khazar's conviction. "I don't know books," Parroulet tells Alan. "I know what is a mechanic. I know what is a priest, a baker, an electrician. But books? How do you teach books? It is just so many words. Like noise on paper." To which Alan initially has no response. Eventually, however, he is moved to explain what it is he does, which is to use books as a means of illuminating life.

It is an ambitious aim and one which surely governs Robertson's approach to his art. The Professor Of Truth is touted by its publisher as a thriller in the mode of Graham Greene or John le Carre, but neither of these writers came to mind as I read it. Rather it operates on another level. Alan is not in mortal danger but on a quest. What he thinks he wants is an answer to a simple question: who really planted the bomb which killed Emily and Alice? But what he discovers is that simplicity is as elusive as truth or justice.

To learn this he must travel to the other side of the globe. His informant is called Ted Nilsen, an erstwhile agent of the American government, who turns up on his doorstep and offers hope of resolution. "We didn't just want to solve the case," Nilsen tells Alan. "We needed to solve it. There's an investment. I'm not talking budgets here, I'm talking emotional capital, mental capital. The bigger the crime, the bigger the investment." Nilsen supplies the name of a place in Australia where Parroulet is now living, having been given two million dollars for identifying Khazar. What option does Alan have but to seek him out?

Thus The Professor Of Truth moves from Old World to New. I don't know whether Robertson visited Australia but his depiction of it is vivid and tangible, especially the blistering heat and the boorish nature of the antipodean male. What is likewise convincing is Alan's ineptitude as a sleuth. "I felt like a student outside his tutor's room, about to deliver an essay or have one returned," Alan recollects as he is about to meet Parroulet. What he wants to hear from him is a confession of his false witness, that he is sorry for implicating an innocent man who is now dead, like Abdelbaset al-Megrahi, the only person convicted for the Lockerbie bombing.

It is a fascinating scenario and one which Robertson handles beautifully. "Tell me, were you even alive before the bomb went off. I mean, really alive?" asks Nilsen of Alan, who insists he was. It is a question that recurs and to which Alan's answer is never wholly convincing. He loved his wife and daughter but did he realise how much until they were killed? It's as if he's taken on The Case out of guilt. This is one of fiction's great strengths, the ability to question the motives even of those who are good. But it takes courage and talent and integrity to do so, of all of which James Robertson has an abundance.

James Robertson

Hamish Hamilton, £16.99

The Professor Of Truth