Murder on Alcatraz — M.L. Hamilton

When a serial killer strikes in the City, Peyton confronts an adversary who is always one step ahead of her. And as the body count rises, Peyton faces a future where her one constant, her partner, may be taken away from her.For eight years, Peyton and Marco have been an unstoppable team; however, one ill-fated trip to Alcatraz may change that relationship forever.