Likeness, The (Dublin Murder Squad #2) by Tana French; 2009. Softcover.

The haunting follow up to the Edgar Award-winning debut In the Woods Tana French astonished critics and readers alike with her mesmerizing debut novel, In the Woods. Now both French and Detective Cassie Maddox return to unravel a case even more sinister and enigmatic than the first. Six months after the events of In the Woods, an urgent telephone call beckons Cassie to a grisly crime scene. The victim looks exactly like Cassie and carries ID identifying herself as Alexandra Madison, an alias Cassie once used. Suddenly, Cassie must discover not only who killed this girl, but, more importantly, who is this girl? A disturbing tale of shifting identities, The Likeness firmly establishes Tana French as an important voice in suspense fiction.