Salem’s Cipher, by Jess Lourey

While the town of Salem, Massachusetts does make an appearance in this mystery/suspense novel, the title refers to Salem Wiley, a young woman whose deliberately uneventful existence in Minneapolis is torn apart by a phone call. She is a genius at cryptography and produced ground-breaking research for her PhD thesis, but her life is severely limited by a form of agoraphobia. The call from her best friend, Bel Odegaard, changes everything.

Police have informed Bel that her mother’s apartment h...