Peter Swanson’s latest novel, “Before She Knew Him,” is a clever take on the serial killer genre. (William Morrow Publisher/HarperCollins Publishers, 309 pages)

Henrietta “Hen” and her husband, Lloyd, attend a neighborhood block party where they meet their next door neighbors, Matthew and Mira Dolamore. The Dolamores invite Hen and Lloyd to dinner one night and give them a quick tour of their home.

In Matthew’s study, Hen spots a fencing trophy. Hen is convinced the trophy belonged to the late Dustin Miller, a student at the private Sussex Hall who had been murdered years ago.

That her neighbor, Matthew, teaches at this school and has a fencing trophy seems to be more than a coincidence. As evidence mounts, Hen is convinced that Matthew is a serial killer.

But the police will not believe Henrietta as she is bipolar and has a history of violence. One night, after too many drinks, Henrietta spots Matthew bludgeoning a musician to death.

The police dismiss her testimony and allow her neighbors to get a restraining order against her.

Matthew Dolamore pursues Henrietta and confesses to her that he only kills men who have been abusive or unfaithful to women. When the signs that Henrietta’s husband, Lloyd, is having an affair, the suspense heightens.

Swanson has crafted a very original plot which will keep the reader in suspense.