I am reading "The Secret Hour" by Luanne Rice.  They synopsis on the back of the book reads:

Beneath his controlled demeanor, attorney John O'Rourke is a man in turmoil.  Since the death of his wife, he has been juggling the rigors of a controversial capital murder case and the demands of raising two children. A woman arrives on the O' Rourke doorstep to find a household in chaos but brimming with love-and she hopes, answers.  Six months ago Kate Harris's younger sister fled from home following a devastating confrontation.  After mailing a single postcard from the New England shore, Willa Harris vanished.

I just started the book and it has the elements of mystery, the exploration of family dynamics and the makings of a love story.  It's an easy read that is hard to put down.