London, Ontario once suffered the highest concentration of serial killers on Earth, and 16 of 29 murder cases were never concluded – but a new book looks to a former detective’s diary entries to offer new theories

Two hours west of Toronto, along Highway 401, lies the small city of London, Ontario.

Known as the Forest City, the town is the birthplace of Justin Bieber, Ryan Gosling and Rachel McAdams. And between 1959 and 1984, it was home to the largest known concentration of serial killers in the world.

Over the course of 25 years, the town was shaken by 29 gruesome murders. Thirteen of those murders were attributed to three killers who were eventually caught and convicted: Gerald Thomas Archer, known as the London Chamber Maid Slayer, Christian McGee, known as the Mad Slasher, and Russell Johnson, known as the Balcony Killer.

Sixteen of the murders have remained unsolved, but a new book based on recovered police files offers a new theory on this bloody chapter in the town’s history, unmasking two alleged serial killers in the process.

Dennis Alsop, a detective sergeant with the Ontario provincial police, was based in the London area between 1950 and 1979. He kept all of his notes and research on the murders hidden until he died in 2012.

“It’s unclear when it all came together, but [Alsop] established this compendium of his original diary entries from the 60s and 70s: old documents from a bygone era, Photostats, teletype transcripts and documents created from now extinct technologies that were thought lost to history,” said Mike Arntfield, a local detective with the London police service and professor at the London-based University of Western Ontario. Alsop left the cache to his son, who ultimately turned them over to Arntfield.

Family and neighbors of a victim help an artist create a composite drawing of one of the killers. Photograph: Western University Archives

Upon receiving the documents and case files, Arntfield set out to identify the perpetrators of the unsolved murders and sexual homicides of the period, using this rare trove of information while drawing on resources from his work in academia and law enforcement.



The peer-reviewed conclusions that are presented in his recently published book, Murder City: The Untold Story of Canada’s Serial Killer Capital, identifies two of the killers for the first time, one of whom is believed to have murdered four children in Toronto after eluding police in London.

“Through [Alsop’s] diary entries, he knew who did it and he was basically stonewalled from making arrests, because they felt he didn’t have enough, they wanted a slam dunk,” said Arntfield. “So he kept tabs on these people on his own time until they moved from London, and it seems that at least in one case there are other victims in Toronto connected to the same killer.”

Based on similarities between crime scenes, and with the help of resources and technologies that were not available to the original investigators, Arntfield concludes that there was at least one and as many as four serial killers operating in London at the time with similar modi operandi who were responsible for the unsolved murders.

But even if all of the remaining cases were found to be the work of a single killer, London would retain the record for having the largest verified concentration of serial killers operating in one place at one time.



“New York and Los Angeles at any given time have had four or five, but London at the time had a mean population of 170,000,” said Arntfield, adding that in megacities like New York and Los Angeles the per-capita equivalent would be about 80 or 90 per city.

Arntfield is no stranger to investigating long-forgotten murder cases. At the university he is the head of the western cold case society, in which civilians volunteer their time to help unearth new information related to unsolved cases using technology that wasn’t available to the original investigators. The club eventually became the subject of a TV series on the Oprah Winfrey Network called To Catch a Killer, hosted by Arntfield.

Why London?

Facebook Twitter Pinterest Downton London, Ontario. Photograph: Matthew Campbell/Wikipedia

What made London such a hotbed for homicidal activity at the time remains unknown, though Arntfield presents a number of theories in his book.



London is commonly used as a test market for major brands that want to introduce new products to Canada. Factors including population size, average income and demographic makeup make it among the most “average” cities in Canada, and one marketers have historically depended on to determine whether a product will succeed countrywide.

American test markets – like Richmond, Virginia, Muncie, Indiana, and Rochester, New York – have all had alarmingly similar histories, with violent crime rates higher than the national average.

“It’s not that having the McRib first or being a test market city makes you a haven for serial killers. It’s that the underlying sociological factors that make those places preferred locales for marketers also seem to see disproportionate numbers of [sexually deviant and violent] offenders,” said Arntfield.

Another factor that stands out is Highway 401, which runs along the southern border of the province of Ontario, and predates the construction of the American interstate highway system by four years.

“Studies have since shown that from ’56 onward, the US interstate changed the criminal landscape significantly,” said Arntfield, adding that the FBI has since developed a highway serial killings initiative to investigate the connection between major highways and serial murders.

Furthermore, the Forest City presents more remote settings than most urban landscapes, while providing access to a large enough population base for perpetrators to pursue potential victims. Such isolated cities also tend to have a lack of informal social control, Arntfield said, and lack the major media and communication networks of major cities.

During this period there was also no formal system for record sharing between police departments, and local, provincial and federal police were slow to identify consistencies between murder scenes.

While the book is intended to shed some light on this dark part of London’s history, Arntfield said it is also intended to provide inspiration to police officers today.

“I’m hoping the book will help empower the cops out there like Dennis and like I was, who stick with a case in spite of department politics, who stick with a case because it’s their calling, who will see things to fruition, whether it’s while they’re still police officers or decades later when they turn over that information,” he said.