Nine liars by Maureen Johnson

Senior year at Ellingham Academy for Stevie Bell isn’t going well. Her boyfriend, David, is studying in London. Her friends are obsessed with college applications. With the cold case of the century solved, Stevie is adrift. There is nothing to distract her from the questions pinging around her brain-questions about college, love, and life in general. Relief comes when David invites Stevie and her friends to join him for study abroad, and his new friend Izzy introduces her to a double-murder cold case. In 1995, nine friends from Cambridge University went to a country house and played a drunken game of hide-and-seek. Two were found in the woodshed the next day, murdered with an ax. The case was assumed to be a burglary gone wrong, but one of the remaining seven saw something she can’t explain. This was no break-in. Someone’s lying about what happened in the woodshed.