"Red John" is a fictional character from the television series The Mentalist. He is portrayed as a notorious serial killer who becomes the primary antagonist in the show. The character is known for his cunning intelligence and ability to evade capture, leaving behind a signature smiley face symbol at his crime scenes. The storyline follows Patrick Jane, a former psychic medium turned consultant for the California Bureau of Investigation. Jane is determined to track down Red John, motivated by the murder of his wife and daughter. The cat-and-mouse game between Jane and Red John forms a central theme throughout the series.