The Associate by John Grisham
For a twenty-five-year-old law student with no criminal record and no illegal habits or proclivities, the presence and the attention of a man who gave all indications of being employed by some branch law enforcement should have caused no concern whatsoever. But it never worked that way with Kyle McAvoy. Streets cops and state troopers didn't particularly bother him. They were paid to simply react. But they guys in dark suits, the investigators and agents, the ones trained to dig deep and discover secrets - those types still unnerved him.