This list covers all minor criminals mentioned in Season Four.
A serial rapist of the power-reassurance type, Clint raped four women and would then ask how he did afterwards. Another rapist, Floyd Hansen, raped and beat a woman to death and then successfully framed Clint for the act.
Selbyville rape suspects
About twenty men who were questioned in connection to Clint Barnes' rapes. They had criminal records with charges ranging from spousal abuse to sex crimes such as molestation and attempted rape.
The serial drowner
A case shown by JJ to Jordan Todd as part of an exercise to determine which cases should have priority. It involved an unsub who drowned two people with one month between the kills. No other details are given.
Another case from the aforementioned exercise, which involved a man who had killed his wife and twin daughters for unspecified reasons. Jordan correctly deduced that case should have priority over the drowner as the man may go after other family members and other innocent people.
The brother of Henry Grace, and an apparently severely depraved serial killer. He was executed after Rossi (who wrote about him in a few of his books, and referred to him as "the face of pure evil") aided in his capture. William's capture ruined his brother's life, and Henry began to believe that because he and brother shared the same genetics (both brothers were born with an extra Y chromosome and Henry believes the outdated theory of the extra chromosome) it made him and his brother killers, despite the fact that the theory had been debunked as little more than "junk science".
A gangster who took advantage of a series of killings targeting Phoenix police officers to attack an officer who arrested him and the officer's partner, killing the former and severely wounding the latter. He is later shot and killed by a police sniper.
Georgia child abductor
The abduction of a boy in Georgia investigated by Rossi. During the investigation, they took the advice of a local psychic which led them in the wrong direction and resulted in the boy's death.
Brad Roberts's abductor
A case in Charleston, South Carolina, which was investigated by Rossi. A neighbor abducted a young boy named Brad Roberts, but he was found and rescued in time. Rossi would later state that the rescue was the proudest moment of his life.
During his killing spree, Father Paul Silvano had a number of unnamed priests act as his accomplices, having them help him capture his intended victims and perform exorcisms on them. The priests were possibly unaware of the fact that Silvano's exorcisms were purely revenge motivated and purposely fatal.
One of the earliest suspects of the case. Not much is mentioned about him, other than that he had a long history of vandalism.
Another one of the case's earliest suspects, he had set his neighbor's garage on fire sometime prior to the episode. Though he claimed it was an accident, he had reported the neighbor the previous month for killing his dog.
Dan and Sarah Murphy
The parents of underage killer Danny Murphy, who covered up his murder of their other son Kyle. After their actions were found out by the BAU, they were presumably arrested.
A police detective and the friend of Dan and Sarah Murphy, who helped them cover up Danny's murder of his younger brother Kyle. He later resigned from his position and was presumably arrested for his assistance was deduced by the BAU.
Jay and Carl
Two gang members who attempted to rob serial killer Vincent Rowlings. Vincent managed to fatally stab Jay with a knife he had on him, but Jay managed to shoot Vincent (who was unfazed by the wound, but died hours later) before dying. Carl fled and called the police to report the murder. He was then interrogated by the BAU, which helped them find out who Jay's assailant was.
The father of serial killer Vincent Rowlings, who killed his wife Kim in a fit of rage after catching her cheating on him. He then fled and was presumably arrested and incarcerated afterwards. His murder of Kim was witnessed by Vincent himself, and would wind up becoming the stressor for his original killings.