The Dead Student by John Katzenbach

'Timothy 'Moth' Turner is a postgrad student and recovering alcoholic. Estranged from his family, Moth's only lifeline is his uncle Ed, a recovered alcoholic and Moth's AA sponsor.

When Ed doesn't turn up for a meeting, Moth gets worried. And he has every right to be. Ed is found shot dead in his apartment in an apparent suicide.

Moth can't believe his uncle would take his own life. And soon, after a little bit of digging, Ed is on the trail of a psychopathic killer known only as Student #5. But why would he want to kill Ed? And who is next on his list...