“Copycat” is a psychological thriller with an intriguing premise. Sarah Havenant is a young doctor who has returned with her husband Ben and their three children to practice in Barrow, Maine, where she grew up. She receives a “friend” request on Facebook from someone she knew in childhood who also plans to return to Barrow. Her friends asks which Facebook page is hers, as there are two. Curious, Havenant checks and discovers there are, indeed, two Facebook pages bearing her name, though she has only created one. The second one, however, has all her personal information about family.

Someone seemingly is impersonating Sarah.

“Copycat” is Maine writer Alex Lake’s third psychological thriller. It starts with great promise. No-frills prose and taut plot development easily pull the reader in. Posts including photos begin to appear on Sarah’s “other” account, including one of Sarah and Ben at a restaurant having an intimate dinner. And photos of her with two girlfriends out to eat. More disturbing, a photo from inside her house showing off her new kitchen. Yet more disturbing still, a photo of her daughter in a school play. Then Sarah receives a request from her other to become Facebook friends. Someone is seemingly stalking her.

Really strange things begin to happen. Sarah goes to the pet store to buy her children a pet goldfish. Later that day she receives a notice she’s been tagged in an online post. No photo, only “Got my goldfish. She’s a beauty.” When Sarah gets home, her husband and children are upset because they found a dead goldfish in a bag in the house. Someone seems to be trying very hard to mess with her head.

Who would do this? A jilted boyfriend from college? Her friend who has recently returned to town? Sarah confides in her friend, Jean, a neighbor and a widow, now single mother of two stepsons. None of it makes sense. Both Jean and Sarah’s husband Ben are distressed and provide unconditional support.

From the start, as the story moves forward, short interspersed chapters give voice to an unidentified tormentor who savors the agony that Sarah is no doubt going through. “The Facebook account is merely the hook that lodges in the mouth of the fish … the fish struggles to free itself, but all it manages is to embed the hook deeper,” the tormentor states. “Fun. This will be fun. Fishing always is. Revenge always is.”

Books from Amazon arrive for Sarah. “Coping with Depression,” and “Living with Bipolar: Family Strategies to Cope with a Bipolar Parent.” Both are ordered on her account.

Her husband’s doubts begin to grow. Then he receives an email from the other Sarah confessing to a tryst early in their marriage. His doubts are now joined by anger.

At the same time, doubts seriously take hold in the reader’s mind, as well. Is it possible, as one therapist friend tells Ben, that Sarah is experiencing fugue states where some secret alter ego possesses her?

The plotting and the glee in the interspersed chapters from the tormenter’s point of view begin to be seen in a potentially alternative light. Is Sarah perhaps crazy?

Though the book is hard to put down, it has numerous weaknesses. Secondary figures show little real character development. And when the plot takes a radical turn two-thirds of the way in, the big reveal lacks impact, if not credulity, because the plot leap is too far without any preliminary scaffolding.

Which is too bad, as Lake has talent for imaginative plotting. Until the major reveal, the reader – like Sarah’s husband Ben – begins to question Sarah’s protests that she is the victim, not the perpetrator. Lake leads us to question her sanity. But Lake forfeits it all by taking the easy path to resolution, failing to truly deliver on the early promise of the story.

Frank O Smith is a Maine writer whose novel, “Dream Singer,” was named a Notable Book of the Year in Literary Fiction in 2014 by “Shelf Unbound,” an international review magazine. His novel was also a finalist for the Bellwether Prize, created by best-selling novelist Barbara Kingsolver “in support of a literature of social change.” Smith can be reached via his website: