John Wayne Gacy, and The Zodiac Killer, are probably the most iconic serial killers of the 20th century.

But can you name a serial killer from the last 20 years?

Unless you're a serial killing nerd, probably not.

The 70s, 80s and 90s were the heydays of American serial killing.

Now, I'm using America as an example in this video, nearly every Western country follows a similar pattern, it's just that you guys have the biggest data set and if I may say so, a penchant for serial killing.

America has 4% of the world's population and 67% of the world's serial killers.

Here's the yearly average for the number of operational serial killers in the US for each decade.

It exploded in the 1970s, peaked in '87 and has been on a steady decline ever since.

We rarely hear about modern-day serial killers.

Either there's just a lot less around, they don't get reported on, or we've gotten really good at catching them.

Technology has made us traceable.

You try secretly eating 17 people today without using a credit card, phone, or the internet.

All while avoiding CCTV. Jeffrey Dahmer had it easy.

The ability to map a suspect's movements over the course of an investigation has radically changed policing, as has DNA profiling.

California had a spree of unsolved crimes between 1974 and 1986.

The police were looking for the Visalia Ransacker, the East Area Rapist, the Diamond Knot Killer, and the original Night Stalker.

But DNA breakthroughs in 2001 linked all 170 cases to the same man.

Now dubbed The Golden State Killer.

DNA allows police to connect unsolved crimes. Let's say they're investigating 5 murders.

This is their search area. But if all the crime scenes are found to contain the same DNA...

The killer is now likely to live somewhere in this smaller area.

With a decent chance of them being fairly central.

Connecting the crimes helps catch the murderer sooner, saving lives.

The Golden State Killer remained unidentified for over 40 years.

Eventually police created a fake profile on a genealogy website, uploading The Golden State Killer's DNA.

They found a handful of third and fourth cousins, built up a family tree.

And were able to narrow it down to just a few suspects.

In April 2018, Joseph James DeAngelo was finally arrested.

In connection with 13 murders, over 50 rapes, and 120 burglaries.

The term serial killer only entered popular usage during the case of Ted Bundy.

Between 1974 and 78 he murdered over 30 young women across 7 states.

Multiple states had separate investigations, all looking for a man of similar description.

With the same car, same victim profile, committing murders in the same way.

These investigations didn't combine forces until after he was arrested.

It was a hard lesson in the importance of communication.

Departments of the FBI were set up to tackle these new types of murderers, using centralized databases.

If police suspected a serial killer they would now submit...

A Violent Criminal Apprehension Program Report, or ViCAP.

This asked for information about the types of victims, witness descriptions...

Locations, the time between murders, staging of the crime scenes —

Anything that could be characteristic to an individual killer.

All reports from across the country would be compared to each other.

Looking for patterns and similarities between cases.

ViCAP was pretty successful and is still used today.

Although it's changed a lot and has been plagued with issues technical and political.

Nevertheless, it taught us that combining resources and intelligence is vital to catching serial killers.

Organizations like Interpol now share data across multiple countries, widening the net even further.

Police aren't the only ones to change. So have we.

Hitchhiking has all but died out, people speak to strangers less.

And young women rarely walk alone in the woods anymore.

The thought of maybe being murdered by that guy behind you, has become increasingly common.

We take more precautions and less risks.

Yet ultimately, serial killing declined because technology, science...

And police procedure are catching murderers sooner.

Potential serial killers are being caught and imprisoned immediately after their first murder.

Or for a different crime, before they even have a chance to start killing.

And once they're in prison, they're more likely to stay there.

Prison sentences for violent crimes have gotten longer and parole has been reduced.

Dr. Mike Aamodt from the Serial Killer Database says...

"Not quite 20% of our serial killers were people who had killed, gone to prison...

Been released and killed again."

By the way, the Serial Killer Database is fantastic.

They have a report comparing IQ scores to killing methods. I'll link it with the sources below.

Since 1987, there's been a 85% reduction in the number of US serial killers.

There's still plenty around, between 20 and 30 are caught a year.

But when they are caught, they have a lot less victims.

If Ted Bundy was around today, he wouldn't have been able to kill so many women, and he wouldn't have gained the same notoriety.

To be a famous serial killer now, you've really got to push the boat out.

Your common old garden serial killer just doesn't make national headlines anymore.

There have been lots of key developments, evidence, and change of procedure

that you can directly point to, to explain the reduction in serial killing.

But the real mystery isn't "where did all the serial killers go?"

It's "where did they come from?"

A key difference between serial killing and your average homicide,

is that victims and their killers are usually strangers.

Serial killers often seek out areas where they're unlikely to know people.

Kevin Haggerty and Ariane Ellerbrok make a case for the 'Society of Strangers.'

The idea being that the 50s and 60s saw unprecedented migration to urban areas.

People went from growing up in small towns where everyone knew everybody,

to cities were the vast majority of the people they met were unknown.

This provided potential serial killers with a wide pool of victims,

while at the same time granting them anonymity.

Another theory is that serial killers just began copying each other.

The 60s also saw the popularization of TV news, true crime documentaries, books, and magazines.

Mass communication allowed stories about the latest murder to spread, gripping the nation like a TV soap.

By the time Ted Bundy appeared on the scene, a celebrity culture had grown around serial killing.

A young would-be serial killer may have found the potential glory and attention intoxicating.

In summary:

the 60s saw huge societal shifts that led to a monumental increase in serial murder,

and it took 40 years for science, technology, and police to catch up.

It would be arrogant to think we now have serial killing under control,

many countries around the world are still seeing continued growth.

The recent decline is a Western phenomenon.

There's no reason it couldn't increase again. After all, we're currently undergoing our own huge societal shifts.

More and more serial killers today find their victims online

and are able to be a lot more careful about their movements and meeting places.

The serial killer handbook is constantly changing, and we need to change with it.

In this video I said the word "sewial killer", "serial killer" 34 times, "murder" 13 and "rape" twice.

There's no way it isn't getting demonitised by YouTube.

So I would like to say a big thank you to Joe Chamberlain and all my supporters on Patreon,

who are the only reason I'm able to make videos like these.

If you want to support the channel, check out the link, and thank you for subscribing.