The difference between a psychologist and a detective is that the psychologist looks to the patient with an eye to unraveling the quirks of the mind, while the officer looks to the evidence. Both men are in the business of gathering information, but their intentions are entirely different.

When Joe O'Loughlin recognizes a murdered girl as a former patient who almost cost him his license, he feels nothing but pity for her poor mutilated body. But the officer in charge, Detective Ruiz, is instantly suspicious, interested in the psychologist's previous professional relationship to Catherine McBride, a nurse who secretly self-mutilated. Ruiz thinks perhaps O'Loughlin hasn't told the whole truth about that relationship.

O'Loughlin has, in fact, kept back some very personal details, thinking the inspector need never know. Catherine developed an attachment to her doctor, not an uncommon event in that discipline, harboring hurt feelings when he could not reciprocate her attentions. But that was years ago, and when decaying and mutilated body is discovered, O'Loughlin is forced to reveal the painful doctor-patient relationship to a very dubious Ruiz.

Conscientious to a fault, O’Loughlin's actions are tempered with the knowledge that he has Parkinson's disease: "So here I am- not so much at a crossroads as a cul de sac." The only certainty that remains is that his body is deserting him by degrees at the age of forty-two.

One of O'Loughlin's regular patient's, Bobby Moran, is experiencing violent dreams that are affecting his waking life, and he has been charged with an assault on a woman, a stranger. O'Loughlin is attempting to guide Bobby through the morass of complications that arise but fearful of pushing Bobby's delicate psyche too far. At the same time, Bobby's behavior becomes more erratic and unpredictable, ranging from ragged grief to excessive rage.

Detective Ruiz demands cogent answers from the psychologist, especially when the evidence points directly at O'Loughin, who is desperate to prove that the police are chasing the wrong man. With limited resources, O'Loughlin does his own sleuthing, getting into a considerable amount of trouble in the process.

Suspect is well-written and engaging. The protagonist is personally flawed, immensely believable in his human inadequacies, yet clearly has a good, if misguided, heart. It is that very compassion for his patients that gets him into trouble in the first place. Even Inspector Ruiz has a quirky character, with his own idiosyncrasies, the perfect foil for the often too-cerebral O'Loughin. London and Liverpool are equally vivid in their differences, lifestyles and citizens. Robotham has created a malleable personality in Joe O’Loughlin, a man well-positioned for more harrowing tales like Suspect.