Lifeguard by James Patterson, Andrew Gross

The perfect job. Working for an easy-going boss at his luxurious mansion by the sun-kissed beach, watching beautiful women walk by.
The perfect girl. Tess - gorgeous, funny, apparently very rich and crazy for him.
The perfect score. Five million up for grabs. And to get his share, all he needs to do is trigger three house alarms to throw the cops off the scent of the real robbery.
Could things get any better for Ned Kelly? But things don't go according to plan. And when Tess is brutally murdered and the others involved in the robbery are massacred, Ned is the prime suspect. With danger at every twist and turn, he's running for his life.