Before She Knew Him by Peter Swanson

William Morrow, 320 pages, $26.99

Hen and Lloyd have just moved into a perfectly cozy suburban home. Hen is an artist and she has a nearby studio. Lloyd does some sort of corporate job, the nature of which doesn’t add to or detract from the story. Their new neighbors are Matthew and Mira. Matthew is a high school teacher and Mira travels for some sort of corporate work, the nature of which doesn’t really affect the story. One of the four is a killer.

Author Peter Swanson has loaded his main character, Hen, with quite a background. Before her bipolar chemistry was leveled with medication, Hen imagined someone at college was a murderer. Now it is several years later and Hen still has some peaks and valleys, but there are no severe psychotic breaks anymore. Lloyd is committed to helping Hen maintain a clear vision of reality. Everything was going smoothly until Hen declared to Lloyd one day that neighbor Matthew is a killer, the murderer of a boy who lived in their old neighborhood. Awkward!

Matthew and Mira obtain a restraining order after Hen calls the police. Not to be deterred by a piece of paper, Hen follows Matthew and investigates someone she thinks may be Matthew’s next victim. Meanwhile, and this is where Swanson takes a different path in his storytelling than others would take, it turns out that, yes, Matthew is a murderer. Oooo.

“Before She Knew Him” is a lively but mostly cerebral story. Even if you figure out one of the main secrets of the story, it won’t matter, because Swanson is still good at tickling the horror funny bone. I really liked Hen. And I really liked Matthew. Go figure!