The Ugly Duckling by Iris Johansen
Nell Caulder is married to businessman Richard. They have a four year old daughter named Jill. At a party in Greece filled with movers and shakers, an attack leaves Richard and Jill dead. Extensive facial damage leaves Nell in need of reconstructive surgery. A bit on the plain side, she is now made beautiful. And ready to go find whoever was responsible for the death of her family.
Nicholas Tanek knows who arranged the attack. Now he has to figure out how to catch him. And Nell is forcing him to let her help.
I read this about a month ago. It kept me entertained at the time, but with the passage of time I've forgotten alot of it. You're told right away who did it so there's not much mystery. But I will read more of Johansen's books.