Suspect. Michael Robotham. 2004.

Doubleday Book Club edition
Joseph O'Loughlin appears to have the perfect life - a beautiful wife, a loving daughter and a successful career as a clinical psychologist. But even the most flawless existence is only a loose thread away from unravelling. All it takes is a murdered girl, a troubled young patient and the biggest lie of his life.

When a young woman is found dead with multiple stab wounds - all of them self-inflicted - the police ask Joe for help. Is this a murder or suicide? The brutalised body he views at the mortuary turns out to be a former colleague, Catherine Mary McBride - and when a patient of Joe’s attitudes  to his own involvement in the murder, O’Loughlin finds himself caught in a complex web of deceit.....