->''"A 60-year-old woman. She did things she never expected to do...Do you wanna hear how, in the evening, she said she would do anything as she begged for her life? Or how, in the morning, she begged me to take her out of her misery? Which do you think I enjoyed more?"''
-->--'''William Lewis''', ''Series/LawAndOrderSpecialVictimsUnit'', "Her Negotiation"; after telling Detctives Benson and Amaro in graphic detail what he did to one of his victims (including putting out cigarettes on her)

Although ''Franchise/LawAndOrder'' features countless killers (and non-killers) who [[MoralEventHorizon committed heinous crimes]] without remorse, many of them have a typical motive such as {{Greed}} and {{Envy}}, or sometimes even a good FreudianExcuse or [[SympatheticMurderer even sympathize with]]. Some however, have the (dis)honor to be called a [[CompleteMonster monster.]]

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''[[AC:Series/LawAndOrder]]''

* [[TheMafia Mafia]] boss [[TheDon Frank Masucci]] was ''Series/LawAndOrder'''s first recurring villain, and one of the worst. [[Recap/LawAndOrderS1E6EverybodysFavoriteBagman Loaning out his henchman]] Antonio "Tony" Scalisi to a group of [[CorruptPolitician corrupt city officials]], Masucci had Scalisi kill Councilman Chuck Halsey on their behalf, then [[HeKnowsTooMuch had Scalisi murdered]] after he was released by EADA Benjamin Stone, leaving the officials to take the fall for a racket he was complicit in. Reappearing in "The Torrents of Greed" "[[Recap/LawAndOrderS1E15TheTorrentsOfGreedPartOne two]]-[[Recap/LawAndOrderS1E16TheTorrentsOfGreedPartTwo parter]], Masucci and his [[TheFamilyThatSlaysTogether brother-in-law]] Harv Biegel sent thugs to assault store owners who [[AnOfferYouCantRefuse refused to buy bootleg cigarettes]], leaving one man dead and one man crippled. Indicted for, among other crimes, the murder of Trucking Union President Russel Mackey, Masucci sabotaged the prosecution by [[BadBoss forcing leg-breaker Joe Pilefski to perjure himself]], and [[YouHaveOutlivedYourUsefulness had Biegel killed]] when he became concerned his brother-in-law was getting ready to turn on him. After Biegel and Mackey's bodies--along with over a dozen others--were retrieved from a mass grave site in New Jersey, Masucci found himself re-indicted, only to be assassinated on orders from his sister, Katherine Biegel, who feared, with cause, that she was next on his hit list.
* Constantin Volsky, the [[TheMafiya Russian mob boss]] from season 9's [[Recap/LawAndOrderS9E23RefugePartOne two]]-[[Recap/LawAndOrderS9E24RefugePartTwo part]] finale "Refuge," ordered an innocent man murdered and dismembered because he had a relative who wouldn't go along with a money-laundering scheme. When he finds out that the key eyewitness for the prosecution is a 6-year-old boy, [[WouldHurtAChild he sends assassins to kill him]]. They kill his mother and an A.D.A. The boy lives, but only because they didn't cut deep enough into his throat. In the second part, he orders the bombing of the precinct where the police protagonists work, [[ForTheEvulz just for giggles]].
* Mark Bruner from the season 14 premier "[[Recap/LawAndOrderS14E1Bodies Bodies]]" [[SerialRapist raped]] and [[SerialKiller murdered]] no less than 17 teenage girls and kept most of their bodies rotting in an undisclosed location so he could go and admire them as they decayed. He terrified his original defense attorney so much that [=McCoy=] helped to get her reassigned, terrified Serena, visibly unnerved Briscoe, Green, and [=McCoy=]. What made him truly monstrous was his refusal to reveal the location of his dumping ground so that his victims might be identified, specifically to torture the parents so that they couldn't find closure, and to torture Jack with the knowledge that he couldn't give them that closure.
* Leon Vorgitch from season 17's "[[Recap/LawAndOrderS17E9Deadlock Deadlock]]" was in prison for killing five people. He then kills two guards and escape from prison. When the detectives come for him it results in even more deaths, including a [[WouldHurtAChild classroom of children]] he had taken hostage (he mistook a truck backfiring for police shooting at him). When Detective Green asks Vorgitch why he killed the kids, he laughs and says "Why not?" In the end, he brags to Jack and Connie that he will escape again and kill both of them.

''[[AC:Series/LawAndOrderSpecialVictimsUnit]]''

* Darryl Kern, also known as The Bowery Stalker, from season 2’s "Manhunt", is a SerialRapist and SerialKiller who made a habit out of abducting, raping, [[ColdBloodedTorture torturing]] and [[WouldHitAGirl killing women]]; his victims numbered at least 30. He was a [[SociopathicSoldier former soldier who was discharged because he believed that soldiers enjoyed killing]]. His journal states that he is planning to survive an upcoming radical war, and create a new generation from {{sex slave}}s, but later admits during questioning that he's simply [[ForTheEvulz having fun at the expense of the police]]. When his hideout is found, at least fifteen bodies, later 18, are found buried in his bunker alone, [[WouldHurtAChild including 3 kids]]. He also has his assistant, a mentally fragile man named Posey, help him kidnap a woman and her young daughter. Kern then [[YouHaveOutlivedYourUsefulness kills Posey]] , and plans to kill his hostages before he is arrested by Canadian police.
* [[SerialKiller Arthur]] [[SerialRapist Blessard]], from season 3's "Redemption", claimed the lives of 21 different [[WouldHitAGirl women]] before he was caught. His MO would involve using [[IntimidatingRevenueService his job in the IRS]] to enter the women's homes, and once given access would proceed to [[BoundAndGagged bind them to their beds]] where he would then beat, rape, and even [[ImAHumanitarian bite chunks of flesh off their bodies]] before strangling them to death. He first started this in 1983, claiming seven victims in New York City before [[FrameUp framing]] a [[DisabledMeansHelpless mentally disabled man]], [[KindHeartedSimpleton Roger Berry]], when the cops were closing on to him. With Roger taking the fall, Blessard went to other cities across the country killing even more women, as well as evolving from strangling to [[SlashedThroat slitting throats]]. After hearing of Roger's release from prison, Blessard returns back to New York and kills more women there, [[KickTheDog all so he frame Roger once more and watch him return to prison]].
* [[GunmanWithThreeNames Matthew Linwood Brodus]], from season 3's "Execution", was a criminal on DeathRow. Prior to being captured he was a SerialKiller and SerialRapist who kidnapped women from different places and took them to his hideout. From there he would not only [[RapeIsASpecialKindOfEvil rape]], but also [[ColdBloodedTorture torture]] them for several hours. The victims would succumb to this and die, at which point he would continue to [[ILovetheDead rape their corpses]]. He has done this to at least 12 women, with the bodies mutilated and disfigured beyond identification. Before his execution could be performed, another victim appeared where he [[EyeScream blinded her]] as well as performing his usual MO. When [[AntiHero Detective Stabler]] sought to get a confession out him so that the victim's family could get closure, Brodus not only confessed to the deed, while showing absolutely no remorse about it, but as a way to [[HopeSpot spite him and the family]] he attacks the detective where prison guards to come then came and brutally beat him down severely injuring him, thus [[KarmaHoudiniWarranty temporarily]] [[KarmaHoudini avoiding his execution]].
* [[DepravedBisexual Charlie Baker]], from season 4's "Dominance", had in the past raped his brother Billy, and then beat up his alcoholic father when they were caught; Charlie continues to beat his father. In the span of a week, Charlie has either killed, or manipulated the weak-willed Billy into killing, around 10 people, but not before forcing them to have sex with each other first. Then he kidnapped two women, killed their boyfriends, and kept them captive on a roof.
* Eugene Hoff, alias Abraham Ophion, from season 6’s "Charisma," is the [[WouldHurtAChild pedophilic]] leader of a CorruptChurch of his [[{{Cult}} 100 followers]], which included his pre-teen victims and their families. Hoff separates the married couples, because he said that they couldn't be soldiers of God if they were slaves to the flesh, and uses all the women and girls of his cult for sexual favors, fathering 1 living and 6 dead children with them. His earliest victim was a 4-year-old Jamie Buchman, who her father caught in the same room with a near-naked Hoff, causing his family to leave the church. Growing paranoid, Hoff began to prepare his followers for war, filling their heads with the idea of the U.S. Government coming to kill them. He was also a {{greed}}y man, killing John Cramer and lying to his wife for John's million-dollar bank account and only keeping his latest victim Melanie alive so he can claim her two-million-dollar trust fund after their baby is born. Hoff is ultimately a depraved individual who [[AGodIAm believes himself to be greater than God]].
* [[GunmanWithThreeNames Victor Paul Gitano]], from season 7's "Fault", was a {{sadist}}ic [[WouldHurtAChild pedophile]] who lured kids in, [[DepravedBisexual regardless of gender]], then [[SerialRapist raped]], [[ColdBloodedTorture tortured]], and [[SerialKiller killed]] them, He had previously molested a 9-year-old-girl, and had also raped and tortured a 12-year-old boy. When trying to hunt Gitano down, things don't quite go as planned. Not only does he kill one of the two kids he had with him in a subway station full of people by [[SlashedThroat slashing the 9-year-old's throat]], but he almost killed Benson the same way. Then, when they corner Gitano in a warehouse, he manages to get behind Stabler and hold him at gunpoint with a shotgun. Gitano, despite knowing he'd get caught or killed at this point, outright boasts that he killed the other child he had, who was only 7, and bragged that she was a "slut" and a "real little whore" before killing her, even though he never got the chance to molest her.
* Luke Dixon, from season 8's "Confrontation", is among the more heinous {{serial rapist}}s in the series. As he thinks that [[PoliticallyIncorrectVillain children with imperfections shouldn't be accepted by the public]], he tries to create a "MasterRace" by impregnating his victims. He operates by using master keys to break in his victims house, forcing them to urinate so he could know their menstrual cycles, and raping them again at the day of ovulation. Dixon has done so to 19 women, including one that he murdered after she confronted him, and another who has been raped thrice and [[DrivenToSuicide committed suicide due to the emotional trauma]]. Finally, before getting arrested, Dixon attempted to kill Detective Dani Beck with a knife. With the unique nature of his crimes taking RapeIsASpecialKindofEvil to a new level, Luke Dixon, despite not having an inordinately large number of victims, managed to stand out in a series dealing with sexual crimes.
* Adam Grafton, from season 12's "Pursuit", is a sadistic SerialKiller and SerialRapist with over forty victims to his name over at least 25 years. Starting as a [[TeensAreMonsters teenager]], Adam would claim his victims—some of whom, including TV host Alicia Harding's younger sister Vanessa, were in their mid-teens at most--in clumps and paralyze them from the chest down by stabbing them in a certain area, rape them repeatedly, and viciously stab them to death to finish them off, but not before stabbing them in their lung, collapsing it and preventing the victim from screaming for help. In the present day, Adam's obsessed with mentally toying with Alicia about his role in her sister's death by stalking her and sending her bloody pieces of old evidence from the case. When Alicia insults him on live TV, Adam flies into a rage and brutally murders [[spoiler:EADA Sonya Paxton]], including before trying to hunt down and murder Alicia, which leads to his arrest. At the end of the episode, even on DeathRow, he coldly and smugly, if not gleefully, tells Detective Benson about all the women he's killed without so much as a hint of remorse.
* [[FauxAffablyEvil William Lewis]]’s [[SoftSpokenSadist soft-spoken]] manner and [[FaceOfAnAngelMindOfADemon good looks]] hide the fact that he is a SerialRapist, SerialKiller, and {{sadist}}ic [[ColdBloodedTorture torturer]], as well as the ArchEnemy of Detective Olivia Benson. Appearing in the season 14 finale and [[ArcVillain in season 15]], his MO is going from state to state, under different aliases, [[WouldHitAGirl kidnapping, raping and torturing women]], [[WouldHurtAChild regardless of age]], for hours and even days on end. When he was young, he watched his babysitter get raped and killed in front of him; he describes it as the best day of his life. Eventually he kidnaps Benson, forces her to watch as he kills the father and rapes the mother of his defense attorney. After [[CopKiller killing a cop]] and taking Benson to a house to rape her, he takes a maid and young girl hostage. When Benson turns the tables on him, he deliberately tries to provoke her to kill him, an experience he makes Olivia relive during his trial. After his escape, he kills another cop, rapes a nurse and kidnaps a young girl. When Benson confronts him, he takes her hostage again, but becomes turned off by his initial molestations, so he decides to force her into a game of RussianRoulette. He ends up fatally shooting himself as one last way of tormenting Olivia, [[ThanatosGambit figuring she’ll be accused of his murder]].

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