Sister

Sister by Rosamund Lupton

'My sister would never have killed herself.' When Beatrice hears that her little sister, Tess, is missing, she returns home to London on the first flight available. But Bee is unprepared for the terrifying truths she must face about her younger sibling when Tess's broken body is discovered in the snow. The police, Bee's friends, her fiancé and even her mother accept the fact that Tess committed suicide. But nobody knows a sister like a sister, and Bee is convinced that something more sinister is responsible for Tess's untimely death. So she embarks on a dangerous journey to discover the truth, no matter the cost.

-FantasticFiction

I found this book, tragic as it was, to be completely riveting.  Nothing can break the bond between sisters. This one rates five stars*****

-Mona