Hemlock House by Katie Cotugno

Last summer there was a murder on Martha’s Vineyard. Now a killer’s on campus in Cambridge.
The follow-up to the New York Times bestselling Liar’s Beach.

More than a year after childhood friends Michael Linden and Holiday Poirot solved a headline-making murder on Martha’s Vineyard, Lindenis ready to start over as a freshman at Harvard—and, he hopes, to reunite with his old girlfriend, Greer. But just as things start to heat up between them, a friend is found dead in Greer’s dorm, Hemlock House.
The police believe the death is the result of an overdose, but Linden suspects there’s more to the story. The victim was wearing Greer’s clothes and sleeping in Greer’s bed when she died . . . and Greer has a long list of enemies. It makes Linden wonder: Was this a case of mistaken identity? Was someone trying to kill Greer? Is she in danger? Is he?
Nearly everyone on campus has something to hide—and some mysteries are better left buried. . . .