Think Twice by Lisa Scottoline

You get grabbed right in the beginning and it does not stop until the end.  There are identical twins and the 'bad' twin takes over.  The 'good' twin figures it out but has a hard time convincing everyone else.  There are many twists and turns and adventures that made this an amazing book to get through.  Scottoline knows how to develop the characters and make you feel for them or even want to take sides.  She is good at showing what people can be capable of and how far reaching their web can be.  Great author.