Every Breath You Take by Judith McNaught
It's the eve of wealthy philanthropist Cecil Wyatt's eightieth birthday but all the money in the world won't bring back his missing grandson, William Wyatt. And the only thing that seems clear so far is that foul play was involved.
The family, the police, the media - all have tried in vain to discover the young man's fate. Now suspicion has turned shockingly toward William's own half-brother, the cool and enigmatic Mitchell Wyatt.
Kate Donovan never dreamed that a chance romantic encounter on a tropical island paradise would lead to her being named as a suspect in a high-society murder case. But after Kate tangles with the darkly charismatic Mitchell Wyatt, she finds herself in serious trouble. As the Chicago police tighten their net, it will take all of Kate's ingenuity to clear her name, and the help of a man who may or may not be a dangerous catch...