This is something of a sequel to The Kind Worth Killing — but I found it much better.

The Kind Worth Saving (2023) is a psychological thriller by Peter Swanson …

The story follows Henry Kimball, a former English teacher and police officer who is now working as a private investigator in Massachusetts.

• The Case: A former student, Joan Grieve, hires Kimball to investigate her husband, Richard, whom she suspects is having an affair. 
• The Connection: Joan and Kimball share a dark past; they were both present during a traumatic school shooting years earlier while Kimball was her teacher. 
• The Twist: What begins as a standard infidelity case quickly turns into a double murder investigation when Kimball finds two bodies in an empty house. 
• The Collaboration: Faced with a case that mirrors his own past tragedies, Kimball enlists the help of his former nemesis/frenemy, the sociopathic but brilliant Lily Kintner, to uncover the truth.