What are the motifs in Plum Island by Nelson DeMille?

Man vs society is a motif. John Corey is a man at odds with authority, teamwork, relationships and regulations. He is an experienced homicide detective who uses wisecracks and illegal procedures to achieve results.

With regards to authority, John ignores Max when he says John is off the investigation. John chooses not to return calls to his NYPD supervisor, knowing his boss is upset with John's involvement in the North Fork case. John taunts Nash and Stevens constantly, verbally battering them into adversarial positions. Even Beth, who he likes, suffers from John's refusal to stop investigating the case.