The first time Dr. Spencer Reid (Matthew Gray Gubler) is not present. At this episode airing date, the only person to appear on every case is Derek Morgan (Shemar Moore).
When making the list of items she needs picked up from her apartment, Garcia asks about Sergio - this confirms that the cat she took in after Emily left is still with her.
Todd Lowe (William Taylor) says to his daughter, "You know Daddy can't sing." Lowe played Zac Van Gerbig in Gilmore Girls (2000), who was the lead singer in a band with Lane (Keiko Agena).
Derek Morgan tells Garcia to search the HSK database. The HSK database stands for the Highway Serial Killer database and is an actual nationwide database used to track unsolved murders that occur in the vicinity of major highways. The database lists specific details about the victimology, M.O., and signature of each murder. This information is then used by the FBI to track potential serial killers in real life.