This list covers all minor criminals mentioned in Criminal Minds Season Ten.
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Steven Parkett's unnamed father
The schizophrenic father of serial killer Steven Parkett, his wife died birthing their son, something which presumably (it's unspecified if he was before) drove him to alcoholism and to abuse his son. His status is currently unknown.
Mark
A man who took photos of underage girls and distributing them as child pornography. His criminal activities caught the attention of the FBI, who eventually tracked him down and sent in an undercover Kate to lure him out. After dating him online for three months, she meets up with him at a bar, and the two go to his room as part of a deal they made: for him to show the pictures he took of the girls. Now with proof, Kate has Mark arrested.
Ludwig
A case in upstate New York that Kate investigated. Absolutely nothing is known about the offender outside of his (presumed) surname. Rossi mentions he looked beaten during his arrest, and that the case must not have been "easy" for Kate, implying some sort of traumatizing detail.
Unnamed intruder
An offender who breached a Port Authority station and assaulted Kate for unknown reasons. He was presumably arrested immediately afterward.
Human trafficking ring clients
At least three men who were clients of a human trafficking ring. One of them purchased a woman who was abducted by Alex Zorgen, Donna Mangold, and Kyle Zorgen at the end of the episode. In the season finale episode The Hunt, more clients are introduced, where it is revealed some of them are women and even families.
Burn
Raymond Leu
The father of serial killer Justin Leu, Raymond entered a downward spiral of alcoholism after his wife died of cancer around 1983. He subsequently became a strict and abusive father, beating them whenever they got a grade less than an A and locking them in a shed for hours at a time. Justin's older brother Todd, unable to cope with the abuse anymore, committed suicide by overdosing on pills in 1988. This led to Justin being taken away from Raymond. He later died from cardiac arrest on August 10, 2014. It's unknown if he was ever convicted of the abuse or Todd's death. Regardless, his actions and his death were the trigger for Justin's psychosis and subsequent serial killings.
Unnamed roadside serial rapist
A serial rapist who would bump his car into those of his victims while on the road, goading them to pull over to check the damage. Once they did so, he would rape them beside the road, with other motorists driving past them without noticing. Kate investigated the case and presumably apprehended the raptist.
If the Shoe Fits
Edward Dunbar
The father of future serial killer Claire Dunbar. He was a pedophile who presumably sexually abused, among other victims, his own daughter. He later abandoned her as a teenager and then went on to be arrested for sexually assaulting two girls in 2002. He then died three years later of a heart attack. While he wasn't abusing her, he would read her bedtime stories of fairy-tales, which would later catalyze her to commit her murders. He wasn't initially found by the BAU due to him changing his surname to Banner and making his wife's maiden name, Rawley, his middle name prior to his arrest.
Boxed In
Sam Bidwell
The father of abductor and indirect killer John David Bidwell, Sam was an alcoholic and religious fanatic who abused his wife Mary and their son. He never let his son go trick or treating on Halloween and always dominated his wife. In 2002, Bidwell went out on Halloween and egged a house. When Sam found out, he locked Bidwell in a trunk and threatened to not release him until next Halloween. When Mary tried to save Bidwell, Sam attacked her and she bludgeoned him to death with a fire poker. Mary and Bidwell buried Sam's body at his father's property where it would remain until it was discovered by the BAU in 2014.
Rodney Tanner
A pedophile who would take photos of young boys. He was arrested in 2013 and incarcerated for abducting a boy named Tommy Wilcox (one of the boys he photographed) and holding him captive before leaving him for dead. Seeking attention, Tanner confessed to the crime but was eventually exonerated the following year by Morgan and Kate when another boy is found and the BAU are called in to investigate. They tell him that he will be re-sentenced and released into the general population of the prison he was sent to, much to his horror.
Hashtag
Charles Lorne
A sporting goods store security guard at a shopping mall who posted an inappropriate image of teenager Tara Harris on social media. The image was illegally obtained from surveillance footage. When Tara was brutally murdered by William Pratt, Charles was considered a suspect after his posts were found and he was arrested by Rossi and Kate. Though he was exonerated of Tara's murder, he was presumably prosecuted for the image he obtained.
The Boys of Sudworth Place
Sean Wallace
A gang member who was Jack Westbrook's client. He was accused of breaking and entering. The prosecutor warns the Jury that he only cares about his fellow thugs, and may escalate to more serious crimes. Jack Westbrook tells them of his abusive family, and how he only had street thugs to turn to. It is implied that he was acquitted.
Sean Wallace's father
Stated by Jack Westbrook to be an abusive man, currently serving 25 to life for an unknown crime.
The Buccieri family
A family of Boston mobsters whose key members were put away by Jack Westbrook during his days as a prosecutor.
The Forever People
Tivon Askari's rapists
A number of individuals who raped future serial killer and torturer Tivon Askari, starting when the latter was ten years old. It is unknown if any of them were caught.
Nelson's Sparrow
Lockport case
A case Gideon and Rossi worked an unspecified amount of time ago in Lockport, New York. No other details were revealed about the case.
Scream
Frank Holden
The father of future budding serial killer Peter Folkmore, who was abusive towards his wife and Peter's mother Karen. The abuse caught the attention of the police, although they didn't have any conclusive proof tying him to Karen's injuries. One night, while in a drunken fit of rage, Frank slashed Karen's throat during an argument before realizing Peter witnessed the whole thing. In shock, he then committed suicide by shooting himself in the head.
Lockdown
Julio Watson's accomplices
Accomplices of Julio Watson who assisted him in committing an unspecified mass murder. All of them were arrested, and Watson, wanting to avoid the maximum sentence, made a deal with the prosecution and left them to be given the severest sentence available.
Russell Landley
An inmate at the Reagan Federal Penitentiary who was a suspect in Patrick Butler's murders.
Domingo Marra
An inmate at the Reagan Federal Penitentiary who was a suspect in Patrick Butler's murders.
Vong Man Giac
An inmate at the Reagan Federal Penitentiary who was a suspect in Patrick Butler's murders.
Southside Crip Nation
A prison-based division of the Crips gang, founded by Julio Watson.
Patrick Butler's accomplices
Several inmates at the Reagan Federal Penitentiary who assisted Patrick Butler in murdering several people connected to Shavers and the fight club. Eventually, by the end of the episode, the inmates were all presumably identified and arrested for their involvement in the killings.
Weeks' accomplices
Several inmates at the Reagan Federal Penitentiary who assisted Weeks in committing a prison riot. After they were let out of their cells by Dale Shavers, they shanked a prison guard to death and then raided an interrogation room holding Morgan, Kate, and Officer Tom Polinsky. They brutally assaulted Morgan and Kate, incapacitating them, while one of them shanked and wounded Polinsky. They then took the three of them to the prison cafeteria, where they intended to kill them. One of the inmates, Don Black, took a sexual interest in Kate and tried to rape her before deciding to beat Polinsky when he began to lose too much blood. The inmate was shot and killed by a police sniper, while the others are arrested by a SWAT team.
Breath Play
The Murphy's unnamed neighbor
A man who lived with his wife as the neighbors of the Murphy family. One day sometime around 1990, the man engaged in erotic asphyxiation with his wife. However, the act went terribly wrong when the man accidentally strangled his wife to death in the act. A then twelve-year old Patrick Murphy witnessed this and was drastically affected by it, causing erotic asphyxiation to become his fetish, and ultimately caused him to become a serial killer. The neighbor was presumably charged and incarcerated for manslaughter afterwards.
Rock Creek Park
Roman Azarof and Taras Yudin
Two Russian mobsters who were hired by Dinah Troy to abduct her daughter-in-law Sophie in order to boost the approval rating of her son Benjamin, a U.S. Congressman. Initially told that the ransom was $2 million, they defied their instructions upon finding out about a large fund acquired by Benjamin, boosting their ransom to $20 million. Later on, Yudin turns on Azarof and kills him for abusing and raping their maid Fana Kedibe, who he was in love with, and then arrives where Sophie is hidden to kill her. However, Dinah tells the FBI where she is being kept, and after Sophie is rescued, Yudin flees and remains at large.
Beyond Borders
Jerry Tidwell's unnamed father
The abusive Dutch father of serial killer Jerry Tidwell, this man would frequently lock his son in a closet, whip him with a belt, repeatedly drown him, among other acts of abuse. All the while, he would never abuse his American wife or stepchildren, leading to Tidwell developing a hatred of Americans. Tidwell finally snapped and killed his entire family in 2004. His birthday was also on April 9, which was when Tidwell would abduct his victims.
Unnamed Thailand criminal
At least one unidentified offender who framed the brother of Lily Lambert for an unspecified crime in Thailand that he did not commit. They took advantage of the fact that the brother was on his first overseas vacation. It is a case Lily has been investigating ever since, and although she had some leads on the case, such as some men her brother was travelling with and a woman he spoke about, they went cold.
Unnamed drug smuggler
A Caucasian man running cocaine in Barbados. He was mistaken for Jerry Tidwell by Hotch and Lily. After he was apprehended, Hotch realized that he couldn't be the unsub that the BAU and IRT were hunting when he checked the smuggler's passport and discovered that he had just arrived in the country. He was then taken to the Barbadian police.
Mr. Scratch
Neil Lewis
Peter Lewis' father, who was accused of child abuse and satanic practices in a group home which he and his wife owned by Dr. Susannah Regan. As the case against him was pending, he was later murdered in prison for being a pedophile and, afterwards, Regan's work was discredited, leading to Peter targeting her and the children who made the accusations in his initial series of crimes.
Neil Lewis' killers
The prisoners who murdered Neil Lewis on prison, thinking he was a pedophile.
Protection
Eddie Parrish
A pimp nicknamed "Sweetness", ironically after Walter Payton (who had the same nickname). He had been picked up for pandering before and was sentenced to two years of probation and a hundred hours of community service. However, Parrish continued his secretive business, loaning some of the money his prostitutes made to his mother. This caught the attention of the IRS. He was a suspect in the murders of Tasha Brooks (one of his prostitutes) and two johns, which were committed by vigilante Danny Lee Stokes.
Herman Koldyke's assailant
An unidentified criminal who stabbed PTSD-afflicted Vietnam War veteran Herman Koldyke during a robbery attempt.
Sandra Cunningham's rapist
An unidentified man who raped a woman named Sandra Cunningham, who was diagnosed with bipolar disorder.
David Ruiz
The ex-husband of Patricia Valdez and the father of their daughter Milena, who was a known criminal in Los Angeles. He was the prime suspect in the April 2014 death of Miriam Stokes, the mother of Danny Lee Stokes, who was his ex-wife's landlady. Ruiz later fled and was arrested in San Diego on February 28, 2015, for armed robbery. His disappearance was what prompted the schizophrenic Danny to commit his killing spree, which claimed the lives of, among others, Patricia and Milena.
Miriam's killer
A burglar who in April of 2014, murdered Miriam Stokes, the mother of Danny Lee Stokes. Nothing more is elaborated on this case, including how or why this burglar targeted and killed Miriam, or if the burglar was ever caught afterwards. Stokes blamed Ruiz for Miriam's murder and presumably never found out the truth about the burglar.
The Hunt
Virginia double abduction
A double abduction in 2011 or 2012 that was fleetingly mentioned in a news report about the abductions of Meg Callahan and Markayla Davis.
Michael Rigby
A client of a human trafficking ring, whose name was given up by an imprisoned Donna Mangold.
Kevin Hawkins
Another client of the human trafficking ring, whose name was also given up by Donna.