A UK criminologist and true crime author has revealed the ideal hunting ground for serial killers — and it’s closer to home than you might think.

Christopher Berry-Dee, who has come face-to-face with notorious murderers, says the internet has become a powerful tool for criminals to identify victims.

“A lot of men [are] like the serial killer John Edward Robinson, the first killer to use the internet for serial killing purposes,” Berry-Dee told The Sun of Robinson, who has been linked to the murders of eight women from 1985 to 2000.

These killers typically go into online chatrooms “as someone else,” masquerading as a businessman, for instance, to lure “lonely women back to his place” and strike.

“People underestimate the internet. It becomes a trawling hunting ground for predators,” Berry-Dee said. “Whether it’s scammers or men who prey on lonely hearts [of] women…it goes way back.”

Before dating apps, there were “lonely hearts” columns in newspapers, where people could advertise they were in the market for love.

Harvey Carignan, known as the “Want-Ad serial killer,” used paper adverts to find victims in need of assistance. He died earlier this month in prison, where he was serving time for murdering three women in Minnesota and Alaska nearly 50 years ago.

The “Lonely Hearts Killers,” Raymond Martinez Fernandez and Martha Jule Beck, found their victims from newspapers that advertised singles, and are believed to have killed 20 people — though the pair were only convicted of one murder.

They were executed at Sing Sing Prison in New York in 1951.

From print to pixels, the “MOs” have remained consistent through the decades, Berry-Dee claims.

“The internet is really just an extension of that, it hasn’t changed. It’s just the method of doing it is electronic now,” he said, calling the internet a “dangerous place.”

Chase Seneca used Grindr, a popular dating app for gay men, to locate victims, mirroring the gruesome crimes of notorious serial killer Jeffery Dahmer.

Seneca pleaded guilty last year to kidnapping and attempting to murder a gay man, and he was sentenced to 45 years in prison.

Authorities say he intended to eat and preserve the bodies of his victims, as Dahmer had done. 

John Wayne Gacy, who was convicted of killing 33 young men and boys in the Chicago area in the 1970s, targeted male prostitutes, teenagers who wanted to work for his company, and hitchhikers.

“Gacy knew where to look,” Berry-Dee said.

“He knew where these weaker people are.”

Despite technological advancement, the approach serial killers take has remained consistent, finding their “hunting ground like an animal” where they know “prey” could be, Berry-Dee said.

Lying in wait, the killers are “patient” until it’s time to “strike.”

“They know where their intended prey swim in shoals, they sniff it out and they’ll watch and they’ll wait,” he continued, “and then they’ll select the weaker one of the herd or the one who has left the group, the one who is walking to a taxi in the rain and he’s waiting.”