Edge - Jeffery Deaver

In Washington, D.C., when Henry Loving targets police detective Ryan Kessler, the investigator and his family are immediately put under government protection.
Loving is a ruthless 'lifter', hired to extract information from his victims.
And he uses whatever means necessary, including kidnapping, torturing or killing their family.
Corte is assigned to guard the Kesslers; an uncompromising officer devoted to protecting his charges.
A brilliant game strategist, he knows how brutal the lifter can be - six years earlier, Loving killed someone close to him.
The situation escalates into a deadly battle of wits between protector and lifter.
But as the lifter closes in on his prey, will Corte protect his charges, or expose them to a killer in the name of personal revenge...?