Speaking in Tongues by Jeffery Deaver

Words are the most dangerous weapons on earth - and Tate Collier, who has a consummate skill with them, can talk his way into anyone's heart, and get them to do whatever he wants.

Tate is a lawyer who used to defend death penalty cases in Virginia's Supreme Court; now he concentrates on work for the local community. When his teenage daughter goes missing all the signs are that she's run away. But Tate and his ex-wife, Bett, feel differently, and set out in search of her. To discover that Megan is in the hands of a man with no morals and as great a gift for words as Tate himself. Megan's is not the only life in danger.