Each of the victims led "a horrible life, that of a drug-addicted prostitute, that ended with a horrific death," Quinet says.
She adds that depraved killers also merit the designation of "worst," but since so many did "the most horrible things you can think of to their victims," she says, "I wouldn't know who to choose."
Quinet says, "My idea of depravity, from a victim's perspective, is what they do to me before they murder me," This would include, "rape, sodomy, choking the victim to unconsciousness but bringing them back only to do it again, keeping them chained as sex slaves for an extended period of time, videotaping the acts, telling them they are going to die, torturing them with various tools, raping victims in front of other family members, burning them, using electric shocks, 'hunting' them and using caustic chemicals like super glue, Drano or bleach."
Kent Kiehl, a professor of psychology, neuroscience and law at the University of New Mexico who has written scholarly works on psychopaths: The Serial Killer Still on the Loose
"I think all serial killers are a 10 out of 10 on the 'worst' scale," he says. "I really don't think their victims would have said it any different. That being said, certainly some serial killers cause more civil disruption and problems than others."
For example, those murderers "who taunt police or victims in the media…can disrupt entire cities and cause mass fear in the entire population," Kiehl says, which "can have terrible effects on police, policy makers and of course, the rest of the population. In a sense, they have many more victims than serial killers who operate in secret."
That said, the worst serial killer is someone who is still out there, not yet caught. "Because they have managed to elude law enforcement," he says, "those smart ones are the most dangerous."
Christine Sarteschi, an associate professor of criminology at Chatham University in Pittsburgh who has published scholarly works on serial killers: Ted Bundy
Although the infamous killer had 36 verified victims, he claimed to have killed more than 100 women. "Part of what was so frightening about him was he could easily fool people with his seemingly normal persona," Sarteschi says, adding that he disarmed victims through his intelligence and charisma, enabling him to slip into their lives without sparking suspicion.
"He was a textbook psychopath," says Sarteschi, who uses Bundy in her classes to demonstrate the psychological disorder. She often plays an interview Bundy gave to James Dobson, Focus on the Family founder, just before the serial killer's 1989 execution.
That interview, she says, clearly showed his psychopathic tendencies because of "the words he chose to use, his avoidance of emotional content, his blaming pornography for his crimes, his referring to himself in the third person and his overall lack of empathy for his victims."
Sarteschi says that students frequently tell her watching Bundy "makes the hair on the backs of their necks stand up."
Mary Ellen O'Toole, a retired FBI profiler who worked on hundreds of serial murder cases: There Is No One "Worst"
"It really isn't a matter of numbers, it's the impact on the victim, family and the community," O'Toole says.
For the surviving family, a loved one's loss is felt for generations. "It creates feelings of helplessness, perpetual grief and sadness," O'Toole says. "There is never closure, and rarely acceptance. It really changes the emotional DNA of the family." Many family members have told her, "it creates a hole in them that can never close."
As for the effect on the community, it can cause panic, particularly if the killer is still active. Citizens experience anger and fear toward the killer and frustration at law-enforcement officers for not catching the person as well as at the media for what can be seen as escalating the situation, she says. "There's a sense of being violated, that such a violent offender has come into their neighborhood and killed people they know and love," O' Toole says.
Candice Skrapec, a criminology professor at California State University Fresno: Harold Shipman
"It's such a subjective judgement," Skrapec says. " 'Worst' has that emotional connotation." She put the question to a group of her honors students and says she could agree with any of their choices. But the name that came up the most was Harold Shipman, a British doctor who killed at least 215 of his patients over more than 25 years, ending with his arrest in 1998.
"He was a medical doctor, he clearly knew what he was doing," Skrapec says, calling his actions "reprehensible." Adding to the horror, she says, was, "the vulnerability of his victims" and that he was able to kill so many people over such a lengthy period of time.
Peter Vronsky, an investigative historian who has written numerous true-crime books on serial killers: The Goofy Beast, Luis Alfredo Garavito Cubillos
Vronsky's pick for "the worst" serial killer is Luis Alfredo Garavito Cubillos, a Colombian-born man known as "The Goofy Beast."
Cubillos—who was convicted of killing 138 boys between the ages of 8 and 16 in South America from 1992 to 1999, he says, is "the worst serial killer in the world overall, in terms of the most number of victims and the 'worst' kind of victim: children."
But Vronsky adds that all victims deserve sympathy, including hitchhikers and prostitutes, who sometimes garner less compassion in the public sphere.
"I'm not suggesting that the life of a sex worker is worth less than a child," Vronsky says, "but as adults they have more autonomy and responsibility for their life and for the risks they take.
"Children don't have that option. Society, in general, looks at any crime targeting a child as 'worse' than those targeting adults."
