How many serial killers are active in the US?

Serial killers in the US remain a terrifying and dangerous phenomenon, but one that also brings a morbid fascination. The media tends to sensationalize and focus on some of the most prolific; everyone has heard of Ted Bundy, Jeffrey Dahmer, and Jack the Ripper.

But how safe are we really? And how many serial killers are active in the US?

Statistically, if you are going to be murdered in the US, it’s unlikely to be by a serial killer. According to the FBI, there are approximately 15,000 homicides each year, and less than 1% are committed by serial murderers, meaning there are about 150 victims each year.

It is very difficult to pinpoint precisely how many serial killers are active at any one time; by their nature, killers tend to go to great lengths to avoid detection.

However, there have been many studies on the topic, and researchers have attempted to estimate the number of active killers based on unsolved murders combined with known serial killings.

Incredibly, of those 15,000 homicides a year, only 60% are solved. This is one of the lowest clearance rates in the Western world.

There are differing theories on the number of active serial killers

The FBI defines a serial killer as someone who murders two or more people. These murders should occur at different times and be classed as a separate event; otherwise, the crime is classed as a mass murder. To complicate matters, some academic institutions and other organizations class a serial killer as someone who murders three or more.

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The FBI suspects there are between 25 and 50 active serial killers in the US at any time. However, this is merely an estimation, and the true figure is a subject of hot debate.

Thomas Hargrove and Michael Arntfield are experts in the field of collecting data on homicide in the US, and they created the Murder Accountability Project, which aims to track unsolved murders throughout America.

Hargrove estimates that there are 2,000 active serial killers. There have been more than 220,000 unsolved killings since 1980, which he attributes to these 2,000. Chillingly, he states, “I’ll say almost every major American city has multiple serial killers and multiple uncaught serial killers.”

Hargrove’s colleague, retired detective Michael Arntfield, disagrees with him and actually puts the number of active killers far higher. He argues that the true figure is between 3,000 and 4,000.

Arntfield fears that many serial killers have become very skilled at avoiding detection, which he attributes to several factors. He argues that killers have learned from TV shows to fool cops by staging scenes and planting false evidence. He also cites an increase in inexperienced detectives and a decrease in funding as a big problem for detection.

Finally, Arntfield suggests that a breakdown in community spirit has led to people not looking out for each other. It should be noted that Arntfield is bucking the consensus here, as most believe that the number of serial killers has dramatically decreased since its peak in the 1980s.

Are there 1000s or 100s of active serial killers in the US?

Kenna Quinet, a criminologist at Indiana University-Purdue University Indianapolis, is far more optimistic about the number of serial killers evading capture. She suggested that there are only about 115 active serial killers dating back to the 1970s.

Quinet’s methodology was based on known links between murders, and she used the three murders or more metric to define a serial killer. She admitted to Live Science, “Somewhere in between my number and Thomas Hargrove’s number is probably the right number.”

Hargrove argues that the true extent of serial killings remains unknown due to “linkage blindness.” This is law enforcement’s inability to link different murders together and their failure to realize one individual is committing multiple murders.

This “blindness” comes mostly from having multiple jurisdictions across the nation. Homicide detectives might never know that a colleague across the state border or county line has a similar case.

There could be between 25 and 50 active killers at one time

Radford University and Florida Gulf Coast University (Radford/FGCU) have created a joint database on serial killings, and in 2020 they produced a report on their findings.

The report stated that using the two or more definition, between 2010 and 2020, there were approximately 48 active serial killers operating each year. And that using the three or more definition, there were 27 per year. These figures only include confirmed serial killers, and they tallie approximately with the FBI estimate of between 25 and 50.

Psychology professor Mike Aamodt at Radford University, who worked on the above report, estimated that between 2010 and 2015, an average of 54 serial killers were operating each year.

Serial killers are a global phenomenon, with Radford/FGCU identifying 115 countries as having at least one multiple murderer. However, the United States leads the world in the volume of serial killers by a massive margin, with England coming in at a distant second.

The US accounts for a whopping 3,613 serial killers, two-thirds of all identified. England accounts for 176 killers, and South Africa, Japan, India, and Canada all had over 100 confirmed.

The number of active serial killers has dropped since the 1980s

The good news is the general trend in both the US and the rest of the world is that serial killings are declining. The number of active serial killers increased rapidly during the 1960s and peaked in the 1980s before, thankfully, dropping back down again. According to World Population Review, 70% of all serial killings occurred between 1970 and 2000.

According to Radford/FGCU, over 800 confirmed serial killers were active in the 1980s, and the deaths peaked in 1987 with 404 confirmed victims. Since then, the numbers dropped to 201 serial killers in the 2010s and only 36 confirmed victims in 2019.

It is unknown exactly why the number rose so high during the latter stages of the 20th century or why it has since dropped. But there are a few theories.

It has been suggested that the 1970s/80s were a period of societal flux when more and more people were on the move. This led to a loosening of community ties and meant people were less likely to know their neighbors. The building of mass transit highways also allowed killers to move large distances without being detected.

At this time, serial killings were scarce; the term “serial killer” was only coined in 1980. Michael Arntfield says the police were unprepared for the onslaught of murderers, and forensic science was still in its infancy.

There is also the intriguing theory that the use of lead in gasoline led to an overall rise in criminal behavior, which then receded in the 1990s after lead was banned. It is not just serial murder but all crime that has been steadily dropping throughout the Western world since the 1990s.

Why are there fewer active serial killers today?

In the meantime, policing methods and forensic science have dramatically improved. The cops are increasingly using DNA to reference genealogy databases to pinpoint the families of killers. Joseph James DeAngelo, aka the Golden State Killer, was recently apprehended this way after evading capture for decades.

Society is now safer than ever. Many serial killers used to prey on hitchhikers, but hitchhiking is much less common today. People take fewer risks with themselves and their children. Cellphones and surveillance cameras also help to keep more of us safe.

Discover Magazine also suggests that the increased use of child psychologists to detect homicidal behavior in children has allowed potential serial killers to get the help they need before it’s too late.

One final theory argues that modern-day serial killers have simply transformed into mass murderers, a phenomenon that has grown rapidly in the last three decades. However, critics of this theory argue that serial and mass killers have different motives and profiles.

Follow the links to read more about the two pictured serial killers, Jeffrey Dahmer and Samuel Little, on Daily Crime.