|“||He is pathological!||”|
Harvey met Caleb Rossmore at the Regional A Chess Tournament sometime in their childhood, and the two became best friends because they shared similar interests, such as in chess and crime journalism. The two became obsessed with the infamous Zodiac Killer and wrote articles about him in their junior high newspaper. His father, Harvey Sr., was also a high school chemistry teacher. In 2000, when they were fifteen, Harvey, having been bullied by another boy at this point, decided to kill the boy's brother Robbie Shaw and convinced Caleb to help him. They killed Robbie together, strangling him to death. They then buried his body in Harvey's backyard, having used sulphuric acid stolen from Harvey Sr.'s workplace to destroy the evidence. The two then drifted apart upon graduating high school, and Harvey eventually became an engineer at a Chinese computer company. He soon became engaged with Marisa Devon, a girl he and Caleb both had a crush on since junior high and chose another man to be his best man instead of Caleb. He also made plans to move to Shanghai without telling Caleb.
Harvey's engagement causes Caleb to snap and start killing in the same style as the Zodiac to get Harvey's attention. After luring Harvey to a secluded location where he is holding Marisa hostage, Caleb confronts Harvey and Marisa, telling the former about their murder of Robbie Shaw, just as the BAU arrive. When Reid tells Caleb about Harvey's plans of moving to Shanghai, Caleb discloses the location of Robbie's corpse and he is arrested. Harvey is also arrested for Robbie's murder.
Since Harvey only killed one person, the term "M.O." is somewhat misused. When he killed Robbie with Caleb, they lured him into a forest, strangled him, and then buried his body in Harvey's backyard.
- December 23, 2000: Robbie Shaw (strangled together with Caleb; his body was found in 2012)
- According to his information from the Department of Motor Vehicles, Harvey's Social Security number is 983-00-0206.