Factual error: When Garcia asks Reid about the IP address of one of the victims father's computer he says "3126.96.36.199." On screen also the IP address of the router can be seen which reads "188.8.131.5294. Neither is possible. The numbers in any IP address can only range between 0 and 255, since they are actually 4 groups of 8 bits each.
Factual error: In the scene where the two unsubs are in the restaurant choosing the next victim, the family they are watching is a Hispanic family that breaks from speaking English for two lines to speak in Spanish. The father asks where the daughter is going, and she answers, "A lavar mis manos," which means to wash my hands. This is incorrect. In Spanish, you would say this as "A lavarme las manos."