The spectrum of human cruelty seems limitless. When it comes to homicide there are many ways that one killing will differ from another. The murder weapon may be one of convenience or brought along with the intent to use it (especially a firearm). Most murders are singular, while others involve taking the lives of an entire assembly. Substance abuse is clearly a factor in certain situations yet absent elsewhere. Some homicides are spontaneous, others premeditated. But despite these disparities, there are only four incentives that drive people to take the life of someone else and they are not mutually exclusive.
Yet, despite the various motives described next, one common thread runs through all of them. The murderer cannot or will not regulate their emotions, wants, or desires. Most have a low frustration tolerance or ability to withstand rejection. Some erupt with the slightest hint of disrespect or judgment. Others have no empathy and hence no interest in delaying gratification. In other words, all murderers want what they want when they want it.
As the examples below will illustrate, having more than one motive is common. And, if someone kills more than once, their motives can change.
These four motives do not apply to accidental or secondary murders (such as poor handling of a firearm or reluctantly killing in self-defense).
Four Motives for Killing
Greed or “Loot” Killings.
According to the F.B.I., monetary gain is by far the most common reason for taking the life of another. It could occur during a robbery, a drug deal gone bad, carjacking, someone who fails to pay a debt, or a home invasion that gets out of hand. This would also include botched kidnappings, human traffickers, and ugly divorces where there is a hefty estate in the offing,
Contract killers are also motivated by money. They see their deadly actions as “nothing personal – it’s just a job.” Some are professionals and others are amateurs. Hired assassins can be found in every major city in the world. The dark web and quiet meetings with gang members are two common avenues to find a hired killer. The prestige and power of the target determine the cost of this “service.”
An example of a profit-driven professional “hit man” would be Jhon Jairo “Popeye” Valasquez. He was also known as “JJ.” Jhon was in the Colombian Navy and then attended the General Santander National Police Academy for a short time. He was the chief assassin for the Medellin Cartel under Colombian Drug Lord Pablo Escobar. Valasquez was involved in thousands of contract killings and kidnappings.
Women are less likely to kill for money but are not immune. An example of this would be the recent arrest of Audrey Miller, 19, and Tiffany Gray, 22. They were charged with first-degree murder in 2024 in Washington D. C. They are accused of killing 53-year-old Fasil Teklemariam, a man they had regarded as their “sugar daddy.” He was stabbed to death. They then severed his thumb to gain access to his banking app. After he was murdered, they returned to the scene of his death (before police discovered the body) to steal several personal items that belonged to the victim.
Vengeance or “Loathing” Killings
Vengeance or anger as a motive behind killing sounds self-evident though it’s not present in every death. Those who kill out of anger may be sick of abuse, jealous, or motivated to silence their victim before they expose damaging information.
When vengeance is motivated by jealousy, they are often referred to as “lust murders.” Murders have occurred even over perceived unfaithfulness.
The Alex Murdaugh murders of his wife and son fall into vengeance killings (in part). He was motivated by two incentives. One was money, as he was in considerable financial debt. But he was also angry because he’d recently been fired and his son knew too much about his scrupulous deeds and was drawing attention. (His wife is thought to have just been at the wrong place at the wrong time.) As such, he was motivated to kill by two different incentives (money and anger).
Another example of a vengeance-motivated killer would be Aileen Wuornos (a.k.a. Aileen Pittman). She confessed to murdering seven men in different locations between 1989 – 1990. She was sexually abused by her family long before she became a full-time sex worker. In that role, she endured frequent physical assault. She claimed that some of her victims raped her and she was exacting revenge. However, her narratives were inconsistent. In an unguarded moment during an interview with a filmmaker, she stated her killings were all in self-defense.
Wuornos is a good example of an individual with multiple motives. She stole from some of her victims and had emotional problems starting as a teen (becoming psychotic toward the end of her life). She sought revenge.
Emotional disturbance.
The root of this broad category is someone with poor mental health. They may or may not know their victim. They think differently than other people and have different values. Their social networks are odd. They may or may not have had contact with the mental health or legal systems. Even their reactions to the death are strange. A few may be indifferent or take pleasure in learning of the deaths.
As someone I know once said, “They are internally disconnected.” Some are competitive and want to “win” the label of the highest body count. Others take perverse sexual pleasure from their actions. A few of the murderers in this group have an agenda, such as the Unabomber who was anti-government and anti-technology. He also had anger directed toward specific people, so vengeance was an incentive as well.
People with severe psychological disturbances may or may not blend into the background of other people.
Another example would be the mass homicide presumably carried out by graduate student Bryan Kohberger in 2022. He was studying criminology at the doctoral level. His capstone project was about “script theory”, which in criminology, is a theory on how and why criminals commit their crimes. He was considered “brilliant” by his professors. Kohberger’s alleged victims were four college students in Idaho. Much is still to be known. The case has yet to go to trial. He likely had no relationship or a weak relationship with his victims, Ethan Chapin, Madison Mogen, Xana Kernodle, and Kaylee Goncalves. All were stabbed to death. There is a lot of circumstantial evidence that links Kohberger to the homicides. Theft was not a motive.
A last example here of emotional disturbance killings would be the mass killer James Holmes. In 2012 he killed 12 people and injured 70 more at a Century 16 movie theater in July of 2012 in Colorado. He had no known criminal background. He came from an affluent background and was raised in the Rancho Penasquitos neighborhood. He had difficulties making friends and tried to end his life at age 11. His girlfriend urged him to get professional help in 2011, which he declined. She left him. Earlier the following year he entered psychiatric care but aborted treatment. His therapist was concerned about his homicide potential but because he never named a specific target nor planned a specific crime, there was no one to warn. He was not motivated by money or lust.
Medically-Assisted Suicide or Mercy Killing
Two key factors here are if the death was involuntary and if someone else assisted. Healthcare providers who take the lives of their patients without their consent are murderers. One example is Harold Shipman from the U.K. He was a family physician who poisoned at least 250 patients. before being stopped.
So-called love killing is not considered murder when done according to the law. Medically assisted suicide is most often carried out with people who have a terminal illness which is causing considerable suffering. When all hope is lost, and the ill person no longer wishes to wait for death, they may request assistance in ending their life. It is a voluntary death.
This protocol is sometimes referred to as “death with dignity.” As of this writing mercy deaths are legal in ten states. There is legislation pending in Pennsylvania, Michigan, New York, North Carolina and Vermont.
The procedure involves making a formal, written request for lethal medications from a physician in a state where it is legal. This may or may not be done with the help of an advocacy group. Some states require the person to ask three times, at least 15 days in between each request. The person must self-administer the medication. If the prescribing doctor believes a psychiatric or psychological disorder is present that is clouding judgment, they can refer. The doctor must also explain alternative treatments, like hospice care. By law, a second physician must review the case and sign off on the first doctor’s diagnosis.
A doctor can prescribe lethal drugs, but never administer them. Almost all assisted suicides today take place in the home, with at least one health-care worker present.
I had a colleague (now deceased), many years ago, who had a father in his early 70s who was slowly dying from cancer. He was bedridden, incontinent, and without an appetite. He did not live in a state with physician-assisted suicide. Hospice care had not yet come into its own in the U.S. He was in too much pain to travel and had no money to do so. He asked his only daughter, my coworker, to end his life. He divulged that he had slowly saved up enough pain meds over several months and knew enough about narcotics and mixing them with alcohol for them to become lethal.
She told me she had been on the fence. If she denied him, he would suffer. He would not ask anyone else to help him. He trusted her. She was told he would “probably” die naturally in several months. She asked her father’s physician to increase his pain meds. They said it would harm his kidneys and refused her request.
She flew out to be with him. She told me later they agreed on a compromise. If he demonstrated he was taking all his prescribed medications as directed for a week, without benefit, she would assist him.
A week passed and he was still suffering even though he was taking his prescriptions as directed.
She mixed the pills he had saved and handed them to him with alcohol. In 25 minutes, he was asleep. In an hour he was deceased. Did she murder him?
