Serpentine by Jonathan Kellerman

A psychologist is pulled into a tense investigation when a string of brutal, seemingly unconnected murders points to a pattern only he can help decode; teaming with an LAPD detective, he applies profiling, forensic insight, and deep knowledge of trauma to follow a trail of clues through Los Angeles’s hidden underworld, confronting buried secrets, moral ambiguity, and escalating danger as they race to unmask a manipulative, elusive killer.

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