For the Sake of Elena:

Elena Weaver was a surprise to anyone meeting her for the first time. In her clingy dresses and dangling earrings she exuded a sexuality at odds with the innocence projected by the unicorn posters on her walls. While her embittered mother fretted about her welfare from her home in London, in Cambridge-where Elena was a student at St. Stephen's College-her father and his second wife each had their own very different image of the girl. As for Elena, she lived a life of casual and intense physical and emotional relationships, with scores to settle and goals to achieve--until someone, lying in wait along the route she ran every morning, bludgeoned her to death. [goodreads.com]