Undercover Thriller

Finished March 29
The Likeness by Tana French
This is a long read, more than 400 pages, but an interesting one. Cassie Maddox is a detective in Dublin and she has recently moved from Murder to Domestic Violence following a difficult murder case that affected her psychologically. (See French's previous book In The Woods for that case.) Back when Cassie first started in the police force she did a spot of undercover work and this case leads her back to that.
Here, a young woman is found dead in an abandoned cottage in a rural area. The interesting things are that she is a dead ringer for Cassie, and she is living under the name Lexie Madison, a name Cassie used years ago when she was undercover. Cassie agrees to go undercover again as this young woman to see what led to her death.
Lexie lives with 4 other grad students in a house inherited by one of them. They are a close-knit group and operate more or less as a family. As Cassie takes on the role of Lexie, she finds herself seduced by the comfort of the situation, and must work hard to keep her mind on why she is there. We see things from Cassie's point of view and therefore are privy to her decision-making process as she determines what to share and what not to share with her superiors.
There are many tense moments and an interesting conclusion.