Another excellent Deaver book (2018). Plenty of surprises.

In the early hours of a quiet, weekend morning in Manhattan’s Diamond District, a brutal triple murder shocks the city. Lincoln Rhyme and Amelia Sachs quickly take the case.

Curiously, the killer has left behind a half-million dollars’ worth of gems at the murder scene, a jewelry store on 47th street. As more crimes follow, it becomes clear that the killer’s target is not gems, but engaged couples themselves. …

… the Promiser makes a dangerous mistake: leaving behind an innocent witness, Vimal Lahori, a talented young diamond cutter, who can help Rhyme and Sachs blow the lid off the case.

They must track down Vimal before the killer can correct his fatal error. …

jefferydeaver.com