The Likeness by Tana French (Dublin Murder Squad #2)

A New York Times bestseller and “pitch perfectˮ (Entertainment Weekly) follow-up to Tana French’s runaway bestseller In the Woods,

Cassie Maddox has transferred out of the Dublin Murder Squad—until an urgent telephone call brings her back to an eerie crime scene.
The victim looks exactly like Cassie and carries ID identifying herself as Alexandra Madison, an alias Cassie once used as an undercover cop. Suddenly, Cassie is back undercover, to find out not only who killed this young woman, but, more importantly, who she was.
The Likeness is a supremely suspenseful story exploring the nature of identity and belonging.