The Likeness by Tana French
My rating: 4 of 5 stars
For once, the blurbs nearly got it right: there is a strong whiff of The Secret History here. As for the mystery part, it's nicely unresolved at the end and readers are left to wonder whether the confession was real, if Daniel is covering for someone because he could and if Cassie will go back to Murder Squad. Because French is writing these from very different POV's it's easy to read this series out of order (as I'm doing).
Somewhere in the book there's a comment that the situation at Whitehorn House could never have continued for ever. It's true: living with a "no pasts" rule, being a young grad student is very different than being in one's 30s or 40s, etc.. so the idea of the group, while interesting, was always frail. There are other ideas floated that stretch credulity, including the very premise of the book, that someone has created an entire identity based on an Undercover Squad creation and who just happens to look exactly like the Undercover agent... thus enabling said agent to go back undercover, as her creation playing the part of the "real thing." Once you get over those bits, it's an interesting read and the suspense part is well done.
Beyond the leap of faith that the premise works, the ending isn't quite as satisfying as it could have been. French seems to rush through explaining who Lexie was before, tracing her journey rather quickly when it might have been better had we seen peeks throughout the story (as we do with her American persona).