For the Sake of Elena by Elizabeth George

A young student at St. Stepen's College, the daughter of a professor up for a prestigious post, is found brutally murdered on an isolated jogging path. Unwilling to turn the killing over to the local police, the university calls in New Scotland Yard. Thus Lynley and his partner Havers enter the rarified world of Cambridge University, where academic gowns often hide murderous intentions. For both officers, the true identity of Elena Weaver proves as elusive as the mythical creature whose image decorated her dorm room. Not until they come to terms with the woman she was will they have a line on the killer--who just may kill again.