The Guilty Plea (Greene and Kennicott #2) by Robert Rotenberg

On the morning his headline-grabbing divorce trial is due to begin, multi-millionaire Terrance Wyler is found dead on his kitchen floor. He's been stabbed seven times. Detective Ari Greene arrives minutes before the international press and finds Wyler's four-year-old son asleep upstairs. When Wyler's ex-wife shows up at her lawyer's office with a bloody knife, it looks as if the case is over.

But Greene soon discovers that the Wyler family has secrets they'd like to keep hidden, and they're not the only ones. And if there's one thing Greene knows, it's that the truth is never simple . . .