The Innocent by Harlan Coben

Matt Hunter's life has already been blown away once. At the age of twenty, he got into a fight outside a party and accidentally killed someone. That momentary lapse of reason cost him four years in gaol, and a small sliver of his soul. But when he got out he set about rebuilding his life. He carved himself a job as a lawyer and married a beautiful woman. The break in the road seems to have only made him a stronger person. However, when he receives a strange video message on his mobile phone and he realises that a very bad man is following him, his new existence is suddenly under threat. Why is this ex-con on his tail, and who really is this woman he has married? Suddenly Matt can't trust anybody - least of all those he loves...