Plot summary
While protecting Justin DeGeorge, the key witness against drug baron Adrian Essex, Van Pelt is knocked out and the witness murdered. His daughter, Trina, probably has crucial memories but her aunt, Jody, refuses to let Patrick question her. The team nabs Essex's accomplice, Eugene Boden. LaRoche is investigating Van Pelt's role is letting the witness die and offers her a positive result if she agrees to spy for him on her team for the Todd Johnson investigation. Announcing that Trina has remembered, Jane and the CBI lure US Marshal Gorman as being the one who was paid to carry out the hit on the witness.
Van Pelt shoots Gorman dead when he attacks her and Lisbon. Van Pelt is cleared and she turns down LaRoche's offer to spy on her team. Agent O'Laughlin proposes to her and she accepts. Trina remembers that she was the one who shot her father in self defense after confronting him about her mother's death.
Credits
Adapted from Wikipedia contributors, The Mentalist season 3. HTML formatting and reference markers removed.