In Stephen King’s macabre short story “The Lawnmower Man,” a sex-crazed landscaper murders and dismembers the suburban homeowner who hires him to cut his overgrown lawn.

The tale ends when detectives arrive and end up trying to gather up the victim’s remains, which are scattered in a backyard birdbath and throughout the expanse of freshly mown grass.

While King’s story is the stuff of fiction, a real-life version seems to be playing amid the manicured lawns and neat flower boxes of Canada’s largest city, where officials are digging for human remains after the arrest of a landscape contractor last month.

Bruce McArthur, 66, was charged in Toronto with the murders of five men. Police say they may be dealing with a serial killer, and that there may be many more victims.

McArthur dismembered his victims and hid their remains in planters, police say. He may have also buried them in the lawns he tended for his clients throughout the city and its environs.

Police have not publicly outlined any evidence, a modus operandi, or the causes of death, and the entire case remains shrouded under a court-ordered publication ban.

“He’s taken some steps to cover his tracks, and we have to uncover these victims,” lead homicide detective Hank Idsinga said at a news conference in Toronto last week.

Police have identified more than 30 properties where McArthur worked in and around the city of 3 million people and are conducting an “extensive” investigation at one residence, where McArthur used a garage to store tools and flower pots, a Toronto police spokesman told The Post. Police have already found skeletal remains of three people in the backyard planters but they have yet to identify them.

The digging began on Jan. 18, when police officers knocked on the door of 53 Mallory Crescent, a sprawling home owned by Karen Fraser and her husband, Ron Smith, on the fringes of the city’s bucolic Mount Pleasant Cemetery.

Police showed the startled elderly couple a search warrant and gave them 20 minutes to vacate the property so they could begin their grisly task. Moments later, several white police vans crowded the street, and officers began to sift through the contents of the garage, stuffed with tools, planters and bags of soil. A few days later, neighbors said investigators erected a large tent in the back yard and began using a generator to thaw the frozen ground in preparation for excavation.

“It really took the two of us to form a sentence and to try and make a plan,” Fraser said in an interview with the Canadian Broadcasting Corp. “I simply couldn’t think. I was so horrified. Every aspect was more horrifying, and I just — it was really hard to take.”

Fraser and Smith, who were briefly allowed back into their home last week, said they had known McArthur for a decade and had allowed him to store his landscaping equipment in their double-car garage in exchange for free yard work.

“You have to understand, he has been kind, helpful, helped with our charity work, doing floral gifts for silent auctions,” Fraser said. “He went above and beyond what our original agreement was to cut the grass. There’s a beautiful Christmas arrangement . . . [that] just showed up . . . a week before Christmas made by him.”

McArthur, a jovial and portly man who was a fixture in the bars and eateries of Toronto’s Gay Village district, had also played Santa Claus at a suburban mall last Christmas, according to his Facebook page, which was taken down shortly after his arrest last month.

Residents at the suburban high-rise where the friendly landscaper rented an apartment told the Toronto Star that he was a keen baker, often showing off his beautifully decorated cupcakes and other confections while he rode the elevator with neighbors.

But buried under the Santa costume and jovial demeanor, McArthur had a dark side.

Thomas Donald Bruce McArthur was born in October 1951. He attended Fenelon Falls Secondary School in the Kawartha Lakes, a mostly rural community in central Ontario whose name is loosely translated from the Anishinaabe language as a place of “bright waters and happy lands.”

Details of his early life remain hazy, but by age 35, McArthur was married, and public records show he and his wife, Janice, bought a home in Oshawa, a bedroom community east of Toronto. The couple have a son and daughter, and McArthur is a grandfather.

While living in Oshawa, McArthur worked as a traveling salesman, selling socks and underwear to department stores across the country. His itinerant lifestyle is part of the reason that police have now widened the search for victims beyond Toronto.

While the McArthurs appeared the very picture of a suburban family, Bruce McArthur carried on another life, frequenting Toronto’s Gay Village, a neighborhood of leather bars and nightclubs that has been a focal point of the city’s LGBT community for decades.

Things began to spiral out of control by the late 1990s, when he and his wife mortgaged their home and later declared bankruptcy. By 2000, the couple sold their home, according to public records. It’s not clear when the couple separated.

A year later, on Halloween night in 2001, McArthur was arrested for beating a man with a metal pipe in the Gay Village. As part of his sentence, McArthur was barred from the district for two years and ordered not to acquire amyl nitrates, or “poppers,” court documents reveal. The drug, often used as a muscle relaxant, is popular among gay men and is sometimes taken before sex.

But despite court-mandated anger management classes, McArthur’s rage continued.

The same day police forensic investigators began searching the Mallory Crescent home, McArthur was charged with the deaths of two gay men — Selim Esen and Andrew Kinsman — who had gone missing last year. Esen, 44, and Kinsman, 49, were last seen alive in the Gay Village.

Kinsman had been romantically involved with McArthur “for some time,” Toronto police said.

In interviews with investigators, three unidentified people who said they had been in sexual relationships with McArthur described him as violent and recalled feeling uncomfortable with some of his sexual proclivities, according to police.

Another man said his training in martial arts saved him from being strangled by McArthur, whom he had known for 10 years.

He “really grabbed my neck, violently twisted it, right to his crotch and his pants were undone,” Peter Sgromo told the CBC. “That’s when I really was quite disturbed.”

McArthur trolled gay websites using the moniker “Silverfoxx.” He had a profile on Recon, a dating site that says it caters to “gay men into leather, rubber, BDSM and kink.” In his profile, he asked to be contacted by “submissive men of all ages,” according to the Globe and Mail newspaper.

Toronto police had been following McArthur since at least last September. They had their first big break last October, when they seized an old, maroon minivan McArthur had sold to a local mechanic for $125. Police found traces of blood in the van, according to news reports.

On the night of Jan. 18, they moved to arrest him when they saw him heading to his apartment with a much younger man and feared for his safety. When they entered his apartment, police found the terrified man tied to a bed, according to press reports.

Last Monday, the macabre story of Bruce McArthur entered an even more chilling chapter after he was charged with the murders of three more men. Dean Lisowick, 47, was a homeless crack addict and prostitute who lived in a downtown shelter. Saroush Mahmudi, 50, had been reported missing in August 2015, and Majeed Kayhan, 58, had been reported missing in 2012.

And, nearly two weeks after they began digging up the back yard at Mallory Crescent, the grisly findings have panicked a city known for its quiet, leafy neighborhoods and a low crime rate. There were 65 homicides recorded in Toronto last year.

A.J. Kahn, who owns a popular bistro in the Gay Village, was frantic last week when he realized he had bought the planters that adorn his eatery from McArthur, a frequent customer.

“Trust me, I’m scared right now,” Kahn told the Toronto Star. “God knows what’s inside.”

For their part, police have said their investigation has moved beyond the gay community.

“We are looking at all missing-person and cold cases, and we are reviewing tips that have been coming in from around the world,” said Meaghan Gray, a Toronto police spokeswoman.

She refused to say if any of those tips originated in New York City. The NYPD said it had not been contacted by Toronto police over the McArthur case.

In Toronto, police now believe McArthur’s alleged victims may also include women. He described himself as “sexually versatile” on the SilverDaddies dating site.

On his dating profile, McArthur wrote, “I can be a bit shy until I get to know you, but am a romantic at heart.”

His next court appearance is scheduled for Valentine’s Day.