This list covers all minor criminals mentioned in Season Twelve.
Earl Roy Everton
One of thirteen serial killers who escaped from prison during the events of The Storm. He attempted to flee to Mexico with the help of an accomplice, but was recaptured through the efforts of Luke Alvez, who lured him out by posing as a coyote.
Carla Jean Birch
The accomplice of Earl Roy Everton, who attempted to help smuggle Everton into Mexico. She was arrested by the BAU after an undercover operation led by Alvez.
Unnamed Seattle spree killer
An unidentified person in Seattle, Washington, who went on a killing spree with an assault rifle. He or she was somehow tracked down by the BAU and either killed or arrested.
Belgian terrorist cell
A terrorist cell of unknown ideology that operated in Belgium. Stephen Walker created a profile for them, but it turned out to be wrong and three undercover agents were killed as a result. However, the cell was still stopped before it could carry out a bombing at a major soccer game.
The D.C. Torso Killer
A still-unidentified serial killer who was active in Washington, D.C., in 2004. He targeted prostitutes, killing them and dismembering their bodies post-mortem, with only the torsos being found, a la the Mad Butcher of Kingsbury Run. The BAU profiled the dismemberment as a forensic countermeasure to prevent identification of the victims, and that the killer was no longer active because he was locked up for an unrelated charge. In 2017, he was believed to have resurfaced after a new torso is discovered in Palm Springs, California, but was ruled out after the victim was found to be male.
A hitman who was hired by a woman to kill her husband, Rossi's friend Judd Ray, during a longstanding domestic dispute. However, Judd survived the hit. The case was brought up by Rossi and Alvez as an example of wives going after their husbands during domestic disputes.
IRT Costa Rica case
A Mexican criminal who was being transferred to Carcel Gran Negra on an unspecified charge(s).
A Mexican criminal who was being transferred to Carcel La Montana on an unspecified charge(s).
A Mexican criminal who was being transferred to Prisión de Máxima Seguridad El Diablo on an unspecified charge(s).
A Mexican criminal who was being transferred to Santa Adeladia on an unspecified charge(s).