Serial Killers: 6 Top Misconceptions

In 1963, forensic psychologist John Macdonald published a paper theorizing that childhood acts of animal cruelty, starting fires and chronic bedwetting could predict who would become a serial killer. Eventually researchers debunked the theory, known as the Macdonald Triad, yet it remained part of serial killer mythology for years.

Today, other myths about serial murderers persist in the public mind.

Marissa Harrison, a Penn State psychology professor and the author of Just as Deadly: The Psychology of Female Serial Killers, says one out of six serial killers is female, which seems to mirror general homicide trends. She also notes that a whopping 39 percent of women who kill worked in nursing or healthcare.

Female serial killers have been around for just as long as male ones. In the early 20th century, Belle Gunness poisoned and dismembered at least a dozen and possibly scores of victims at her Indiana farmhouse In the 1980s, Aileen Wuornos drew national attention for killing at least seven men on the highways of Florida.

Harrison tells A&E female serial killers may initially go unnoticed due to how they typically kill. "[When] somebody is dying via poison, you might not recognize that this was a murder at first," she says.

Gender stereotypes may also play a role in these murderers escaping attention. "People don't think that a woman is capable of doing this type of thing," Harrison says.

The words "serial killer" often evoke the image of white men like John Wayne Gacy, Ted Bundy or Jeffrey Dahmer. Mass media has long reinforced that white male archetype, both in its true-crime coverage as well as through popular culture characters like Norman Bates, Hannibal Lecter and Dexter.

Yet just as not all serial killers are male, not all are white.

In 2008, the FBI updated its definition of serial killing to: "The unlawful killing of two or more victims by the same offender(s) in separate events." Under this definition, contract murderers and some perpetrators of gang violence are also considered serial killers.

According to the U.S. Department of Justice's National Gang Center's most recent national gang survey, law enforcement agencies have reported that 46 percent of gang members around the country are Hispanic/Latino, 35 percent are African American, 11.5 percent are white and 7 percent fall into other races and ethnicities.

In the seventh edition of Serial Murderers and Their Victims, Eric Hickey, who teaches forensic psychology at Walden University, writes, "Based upon the FBI definition of a serial killer, between 2004 and 2014, controlling for race and gender, 50% of all male serial killers in the United States were African American."

Enzo Yaksic, founder of the Atypical Homicide Research Group and author of Killer Data: Modern Perspectives on Serial Murder, tells A&E True Crime via email, "African Americans are certainly overrepresented among the serial murder offender population. It is not that there are more African American serial murderers today, but rather a wider acknowledgment that they exist, which led to an artificial increase in their numbers over the years."

Hickey also writes, "The rise in African American serial killers is also directly related to how the FBI now defines serial murder."

However, Black female serial killers, specifically, are extremely rare.

Serial murderers of other races are also infamous across the world.

In the 1990s, Ángel Maturino Reséndiz, the Railroad Killer, murdered people near railroad tracks across the U.S. From 1984 to '85, Richard Ramirez, the Night Stalker, killed people in California. China has seen "Monster Killer" Yang Xinhai, who took more than 60 lives in the early 2000s. In the 1980s, Charles Ng, who was born in Hong Kong, killed multiple people in California along with a partner, Leonard Lake.

When police suspect a serial killer may be at work, they sometimes ask criminal investigative analysts (also known as criminal profilers) to develop a profile of the murderer. However, Peter Valentin, a professor at the University of New Haven and a retired Connecticut state police detective, tells A&E True Crime the profile may be of limited use to an investigation.

"If we're looking for a white male between 20 and 40, who has a secondary education, what do I do with that information? It's so nonspecific...it doesn't really help."

"Ultimately, I need to establish their guilt through physical evidence," Valentin adds. "The more unusual the connection between your victim and your offender, the more you need physical evidence or other documentation."

Profiling can even send investigators in the wrong direction.

While on the hunt for the elusive "Unabomber," the FBI believed their target was a young white man who was college-aged, possibly a blue-collar worker who was adept with tools. Theodore Kaczynski, who was in his 30s when the Unabomber first struck in 1978, and who enrolled at Harvard at 16, was initially dismissed as a suspect. According to the New York Times, “For years, agents dreaded the endless assignment [of searching for the bomber]. Computer searches turned up little because agents focused on men 10 years younger than Kaczynski.

In 1984, Gary Ridgway, the Green River Killer, sent an anonymous letter to the Seattle Post-Intelligencer. At the time, a profiler from the FBI declared the letter writer "has no connection with the Green River homicides."

Fictional serial killers are often portrayed in books, TV shows and movies as leaving behind a signature each time they kill. Their kills are typically shown as progressing in severity.

Reality doesn't fit this pattern.

"The notion that offenders leave unique signatures at every scene is not supported by the data,” writes Louis Schlesinger, a psychology professor at John Jay College of Criminal Justice, in his co-authored 2010 paper, "Ritual and Signature in Serial Sexual Homicide." “Although almost all the offenders in our sample engaged in some form of ritualistic behavior, they rarely engaged in exactly the same behavior at every murder."

Schlesinger tells A&E, "We found in our research 70 percent of serial sexual murderers experiment at a crime scene. They do something different with one victim that they didn't do with the other victims in their series."

According to Schlesinger, one third of the time a killer will stage a different attack on an early victim, one third of the time it will be a middle victim and one third of the time the killer's varying form of attack will be on a victim at the end of their series of murders.

Schlesinger says, "The type of serial killer that we know most about and that most research is done on is the serial sexual murderer...where the murder itself is sexually motivated."

Yet there are many other kinds of serial murderers. Medical personnel have killed patients in their care. Other serial killers have been motivated by money or for political reasons.

"There's a world of difference between a serial sexual murderer like the Boston Strangler [Albert DeSalvo] versus a contract killer doing it for money," Schlesinger says.

"Serial murder typologies are in desperate need of a serious review by modern serial murder researchers to bring them more in line with the reality of who these offenders are today and how they operate in the modern age," Yaksic says.

Schlesinger says, "The American public wants their serial killers to be evil geniuses, with IQs of 160 that speak five languages, including Aramaic, that are connoisseurs of fine wine. Nothing could be further from the truth."

"The Green River Killer [Gary Ridgway]...his IQ was 81," Schlesinger adds. "Even the ones [who] went to college—which is rare, like BTK [Dennis Rader] or Ted Bundy—they didn't use their intelligence in any significant way that I could determine."

"The majority of serial murderers are not exceptional or unique, but rather run-of-the-mill hometown losers," Yaksic says. "They are not infallible charming killing machines who are experts in remaining one step ahead of law enforcement."