Odd mystery, Great Ending & Awesome book!!

This book is different then lots of mysteries I have read. At first I was confused, In the middle I was hooked to it and by the end I didn't want it to end.
The book is about the Mystery " Who killed Mr. Westing?" As you get to the middle and end it turns into " who is Mr. Westing, really?"
Their are 16 heirs in the book! One is a thirteen year old girl, who's sister, another heir, is a bomber, a fiance, and nice lady. One other heir is a chinese restaurant owner that had it's restaurant bombed. One is a judge who used to play chess with Mr.westing, and many people like that.
The story has so many turns and twists. Here are some:
There are four bombings in Sunset Towers ( were everyone lives)
Mr. Westing isn't who you think he is
Three people go to the hospital
Two couples get married
&
There is one song that puts part of the mystery together,
This is such a good book. I would recommend this book to Anyone who likes a good mystery.