The Kept Woman by Karin Slaughter

 In The Kept Woman, GBI agent Will Trent comes upon a crime scene and thinks his estranged wife Angie might be dead. Or she might have staged the whole thing to torment him, which is something Angie would do. Will is a mess. His girlfriend Sara is furious that Angie is still interfering in their lives just because she can. His partner Faith has been saddled with an Atlanta cop who won't stop talking and may have his own agenda. And the GBI is stumped at trying to figure out what really happened--and where a missing 6 year old boy is. Quite the page-turner.