One day in March 2014, Harold Peerenboom received an anonymous letter. The envelope was addressed to his home in Sloan’s Curve, a luxury gated community in Palm Beach, Fla. “In September we heard around the neighbourhood that you had died in a car accident,” the missive read. Peerenboom, a wealthy Toronto businessman, had been hospitalized after a crash a few months prior. “I was looking into buying my ticket to go to Canada so I could spit, dance, urinate and deficate [sic] on your grave,” the letter continued. “Then found out you cheated death.”

The author and a “helpful assistant,” according to the letter, had spent tens of thousands of dollars on research, postage and envelopes to send mail to prison inmates in Florida, Alabama, Georgia and Canada, along with their mothers, spouses and girlfriends. “I wrote the prisoners on your behalf and challenged them to come see you!” the author claimed. “No one will be happy until you leave our neighbourhood—until you leave Sloan’s Curve—get out now.”

The author included copies of the letters purportedly sent to prisoners, which listed Peerenboom’s address. “Look scumbag, you waste time and space on this earth,” read one. “When you get out of jail—come see me—I will kick your ass.” It was signed, “Harold your worst nightmare Peerenboom.”

The letter marked a new variation to a bizarre hate mail campaign against Peerenboom. Previous batches of letters—mailed to friends, neighbours and colleagues—falsely accused him of being a child molester and an anti-Semite. Now came an attempt to incite violence against him and his family.

Peerenboom contacted police as soon as the first hate mail appeared in 2012, but he also opened his own investigation, contributing to a widening gyre of litigation that has pulled in friends, neighbours, private investigators, high-powered attorneys and police forces in the U.S. and Canada. In five separate lawsuits and thousands of pages of court documents, there are allegations of character assassination, DNA theft, extortion and even accusations of murder.

And the whole debacle began, according to Peerenboom, with a dispute about tennis courts.

On a long, thin strip of land next to West Palm Beach sits Sloan’s Curve. The residences are surrounded by water—a lagoon on one side and the Atlantic Ocean on the other. Behind gatehouses staffed 24/7 are four upscale condo towers and 22 houses, some boasting swimming pools and walk-out access to a sand beach.

It’s the kind of setting that appeals to business moguls and executives approaching (or long past) retirement age. Former Canadian senator Leo Kolber owns a property there, as does designer Brian Gluckstein. Perhaps one of the wealthiest residents is Isaac Perlmutter, 74, the reclusive CEO of Marvel Entertainment. Forbes estimates his net worth at US$4 billion.

Harold Peerenboom, 70, has much in common with this crowd. In 1970, he founded Mandrake, a headhunting and consulting company employed by Molson, Hasbro Canada and other major corporations. He also co-founded Crestwood, a tony Toronto private school, served as chair of the Toronto Harbour Commission and launched an annual hockey event that raises money for children’s charities. Last year, he purchased Conrad Black’s Bridle Path mansion in Toronto for $14 million. (Black and wife Barbara Amiel are tenants.)

In 2010, Peerenboom and his wife, Robin, moved into a townhouse in Sloan’s Curve. He later joined one of the residents’ associations (separate entities govern the townhouses and condos). Residents, he would learn, were passionate about the tennis centre.

Sloan’s Curve has six courts and a pro shop. Since 1988, the facility has been run by Karen Donnelly, a native of Rhode Island. Divorced with two sons, Donnelly became close with many residents over the years. She offered tennis lessons, and could sometimes be found on the courts, calling out directions or tips to her students in a New England accent. “My friends, including my husband, who plays tennis and utilizes Sloan’s Curve, have enjoyed her services and all care deeply for her,” Isaac’s wife, Laura Perlmutter, said in a deposition.

Although Donnelly enjoyed her job, she decided to branch out and get a real estate licence, thereby allegedly offending Monique Matheson, a go-to agent for many residents. (She did not respond to interview requests.) “There was a lot of jealousy here between Monique Matheson and Karen,” Perlmutter said in a deposition. “All of a sudden she has a threat now. There’s another lady selling real estate.”

Matheson’s husband, Bill, raised concerns about Donnelly’s role at the tennis centre. A retired lawyer, Bill protested to the Sloan’s Curve Homeowners’ Association (SCHA) that, by law, the contract to operate the tennis facility had to be put out for competitive bids. Instead, the SCHA board awarded it every year to Donnelly. Bill found an ally in Peerenboom, who wanted to ensure the board was fiscally responsible.

Word spread around Sloan’s Curve of an effort to oust the tennis director. Around 100 people showed up at a meeting to support Donnelly. Perlmutter was there and Peerenboom claims he stood up at one point and began chanting, “We will not be intimidated.” (Roy Black, Perlmutter’s attorney, says this never happened.)

Peerenboom later prepared an unsigned memo titled “Facts all prudent owners should know,” a bulleted list of issues with Donnelly and the tennis contract. The message accused the board of “bid rigging” to award the contract to Donnelly, a federal offence. He brought the memo to an SCHA meeting for discussion and handed it to Richard Bornstein, a board member. Bornstein later gave a copy to Perlmutter, who passed it along to another board member at the swimming pool. Someone left a copy on Donnelly’s desk.

Peerenboom said his grievances had nothing to do with the tennis pro personally. “We had no interest at any time in getting rid of Karen Donnelly,” he said in a deposition. (Through a spokesperson, Peerenboom declined to comment for this piece.) “We had an interest in trying to bring financial constraints to everything we were involved in.”

Peerenboom felt he was being shunned for his advocacy. The condo association allegedly restricted him from accessing his storage space. He blamed Laura Perlmutter for excluding his wife from a long-standing card game at a nearby country club. Laura said later she wasn’t ostracizing anyone. “If she needed a game tomorrow and I was sitting there, it may not be my preference, but I certainly would be cordial and lovely to her,” she said in a deposition.

In 2011, Donnelly sued the Mathesons for defamation, alleging the anonymous memo created a “false impression” of her and interfered with her real estate business so that Matheson could corner the market. Peerenboom was deposed as a witness and revealed that he was actually the author—which resulted in Donnelly suing him, too. Peerenboom sought to have the case thrown out, arguing that he never distributed the memo around Sloan’s Curve. (The Mathesons also fought the suit and denied the accusations.)

As the case wound its way through court, a new detail emerged: Donnelly was not paying for it herself. Her lawsuit was financed by two Sloan’s Curve residents—one named Stephen Raphael, the other Isaac Perlmutter.

“I felt sorry for this lady, single mother with two kids, over age 50,” Perlmutter would say later. “I feel that they’re looking to push her out, and I’m looking to help her.” The feuding had disrupted the tranquility he had known in Sloan’s Curve for more than 20 years. “To me, it’s stupidity,” he said in a deposition. “Suicide for no reason because greed and money and jealousy, and I like to see peace.”

Outside of Sloan’s Curve, Perlmutter has a reputation as a mysterious figure. It appears he has never given an interview, and until last year, the only photo of him in wide circulation was taken in 1985. Last December, a news photographer snapped a shot of him standing with Donald Trump behind a window at Mar-a-Lago, the U.S. president’s Florida estate. The two have reportedly known each other for years. At a press conference in January, Trump praised Perlmutter and said he was “very, very involved” in advising the president’s veterans affairs team.

The mogul is an Israeli-American and a veteran of the 1967 Six Day War. According to Forbes, he immigrated to New York with $250 in his pocket and sold toys on the street, eventually starting his own company. Perlmutter later sold Marvel-branded products and became close to the firm. He tried to persuade the owner to branch into the movie business, but his advice was rejected. After Marvel filed for bankruptcy in 1996, Perlmutter gained control. He’s credited with rejuvenating Marvel, selling it to Disney in 2009 for US$4 billion. He stayed on as chairman, maintaining a tight grip.

In December 2012, more than a year after the fight over the tennis contract started, Perlmutter’s condo in Sloan’s Curve was one of 189 residences to receive a vile letter. The author purported to be a grandparent whose 11-year-old grandson was sexually assaulted by Peerenboom at knifepoint. The letter contained the phrase “dafuk barosh,” Hebrew curse words meaning messed up in the head. A few days later, another batch of letters arrived for Peerenboom’s colleagues at Mandrake in Toronto. Each wave consisted of the same letter, typed and unsigned, and purporting to be sent from West Palm Beach.

The following month, about 200 more letters were sent to residents at Sloan’s Curve, Mandrake employees and their spouses, levelling a new allegation: Peerenboom was responsible for murder. In early January, David Pichosky and Rochelle Wise had been found asphyxiated in their townhouse in Hallandale Beach, about an hour’s drive from Palm Beach. Wise had been a long-time director at the Toronto private school Peerenboom co-founded. The letters falsely claimed Peerenboom was involved in their deaths, allegedly blaming Wise for the child abuse accusation contained in the earlier round of hate mail. (The homicide investigation remains open.)

Peerenboom began developing a list of suspects who could be behind the mailings. In February, Isaac and Laura Perlmutter were deposed as witnesses in Donnelly’s defamation suit, and Peerenboom’s lawyer asked them about the hate mail and showed them a printout of the Hebrew slang. Isaac expressed sympathy. Peerenboom had previously offered $100,000 for information leading to the arrest of the culprit, and Perlmutter wanted to help. “I’m offering on the record here another hundred thousand dollars to help catch the guy,” he said.

Perlmutter may not have known it then, but he was a prime suspect.

After the first batch of letters were delivered in December 2012, Peerenboom contacted the Palm Beach police. A detective named Larry Menniti met with him, and Peerenboom outlined the controversy around the tennis centre. “Mr. Perlmutter was suspect from the onset,” Menniti said later in court. As far as Peerenboom was concerned, there were plenty of reasons for suspicion: Perlmutter’s love of tennis, his apparent devotion to Donnelly, the strong possibility he knew Hebrew slang and, of course, his bankrolling of a lawsuit against Peerenboom.

He asked Menniti about collecting DNA samples from the letters, but Menniti said the department couldn’t afford it. Peerenboom offered to pay, and when the detective demurred, Peerenboom asked whether the police could use DNA results processed by a private facility. Menniti recalled saying he preferred citizens didn’t conduct their own investigations, but he would consider any evidence provided to him.

Peerenboom hired a company called Speckin Forensic Laboratories to help obtain DNA samples to compare against the anonymous letters. In February, an employee named Michael Sinke showed up at the Palm Beach law office where the Perlmutters were being deposed for Donnelly’s defamation case. A middle-aged man with neatly trimmed hair and glasses, Sinke wouldn’t look out of place in a room full of lawyers.

Sinke came armed with a few documents containing Hebrew slang, printed on pristine, special paper designed to collect DNA. He told Peerenboom’s lawyer to hand the papers to the Perlmutters by the top corners during the deposition, and get them back without touching them. Sinke was mute throughout the depositions. When the interviews finished, he snapped on a pair of gloves and placed each sheet into a clean plastic sleeve. Laura’s water bottle and a discarded bottle cap were collected too.

Later, Peerenboom received a phone call from one of the owners of the forensics lab. “We have a hit,” the owner said, according to Peerenboom.

“Who was it?”

“Laura Perlmutter.”

In October 2013, Peerenboom launched a legal blitz against his perceived antagonists, even with the police investigation still underway. He asked the courts to compel nearly a dozen individuals, including the Perlmutters and Donnelly, to turn over emails, internet histories, phone records and samples of paper stock and printer ink, as well as DNA samples and fingerprints. Lawyers for the defendants fought to have the claims tossed out, likening Peerenboom’s demands to “the McCarthyist search for communists.” A judge agreed and dismissed the motion, but Peerenboom later filed an amended complaint naming just Isaac and Laura Perlmutter.

He claimed that veiled threats were made by “various agents of Perlmutter” that Isaac would “crush” Peerenboom. It would only stop if he withdrew from public affairs in the community.

The Perlmutters say the suit is baseless and filled with unreasonable inferences. Both men enlisted high-priced lawyers. Peerenboom is represented by Marc Kasowitz, who’s also outside counsel to President Trump. Perlmutter retained Roy Black, a criminal defence lawyer known for representing Rush Limbaugh and Kelsey Grammer. (His wife, Lea Black, starred in The Real Housewives of Miami.)

In June 2014, Kasowitz’s firm sent a letter to Black’s team explaining that the Perlmutters’ “DNA may be among DNA samples tested by a DNA lab.” Until then, the Perlmutters had no idea their genetic material had been collected. And they were not the only targets of Peerenboom’s investigation, it turns out. He also suspected Raphael, who had co-funded Donnelly’s defamation lawsuit. Peerenboom teamed up with a neighbour to root through Raphael’s trash and collect bottles to test.

In court, the Perlmutters deposed Peerenboom’s former lawyer in the defamation lawsuit, William Douberley, and grilled him about his role in the DNA plot. The lawyer asserted attorney-client privilege in response to a number of questions. The court ended up holding a four-day hearing last year to determine whether Douberley should have to answer. The Perlmutters argued that the testing scheme violated a Florida statute prohibiting DNA analysis without the “informed consent of the person to be tested.” They contended the entire deposition was a ruse, in fact, and that Peerenboom and Douberley perpetuated a fraud on the court.

During the hearing last year, Peerenboom testified that he kept the Palm Beach police informed of his actions and nobody told him to stop. Even though he learned about the statute prohibiting covert DNA testing, Peerenboom said he was assisting the police and thought he would be in the clear. “I was always working on behalf—as an agent for the Palm Beach Police Department,” he said. Menniti said that Peerenboom was not working undercover and that he tried to dissuade him from conducting private DNA testing.

In a decision issued in July 2016, the judge granted the Perlmutters’ motion to compel further testimony from Douberley, and noted that she did not find Peerenboom’s testimony credible. She wrote that Peerenboom knowingly violated Florida’s DNA statute and that he and Douberley acted “fraudulently” when deposing the Perlmutters. (Douberley appealed, and the court remanded the matter to the trial court on the grounds that he never received notice of the hearing.)

Shortly afterward, the Perlmutters sued Peerenboom, Douberley and Speckin Forensic Laboratories, alleging they carried out “an international conspiracy to surreptitiously and illegally collect, analyze and disclose the Perlmutters’ genetic information.” The counterclaim also alleges the DNA results linking Laura to the hate mail were distorted. Speckin outsourced the testing to another company, which found Laura was not a match. Speckin, under pressure from Peerenboom, reinterpreted the results to show that Laura could not be excluded as a suspect. Peerenboom denies putting pressure on Speckin and is seeking to have the counterclaim thrown out. (The forensics company also denies the claims.)

Perlmutter also contracted at least three private investigators to dig into Peerenboom, listing in the counterclaim numerous disputes and lawsuits dating back to the 1980s, including one with a neighbour in 1997. Peerenboom planned to build an indoor pool and gym in his backyard in Toronto, aggravating nearby residents. When his next-door neighbour voiced concerns about security, Peerenboom mounted high-intensity lights to the wall of his home, which shone 24 hours a day into the adjacent bedroom. A politician named John Adams also spoke out against the renovation, so Peerenboom called various Adamses around Toronto offering them financial incentives to run in the next election in an attempt to confuse voters. “Has it got nasty?” he said in a newspaper article at the time. “Yes.”

Peerenboom’s legal team denounced these efforts as an attempt to smear him by dragging up irrelevant disputes. The Perlmutters contend he is a man with many potential enemies. Meanwhile, the hate mail kept coming. Since 2012, more than 1,300 pieces of hate mail have been sent in 15 separate salvos, according to court documents.

In January 2016, customs officials in Detroit intercepted a package en route from Toronto to Miami. It’s unclear what raised suspicion, but officials decided to open it up. Inside were latex gloves and letters addressed to Robin Peerenboom. The author threatened to mail prison inmates accusing Harold Peerenboom of being a child molester unless he left his Palm Beach home.

Authorities sent a dummy package in its place, while law enforcement officials waited outside a UPS store in Miami for someone to pick it up. Nobody did. Homeland Security contacted federal authorities in Canada, who learned the package had been sent in the name of a former employee of Mandrake, Peerenboom’s company. Investigators interviewed the man, who seemed unaware of the matter. According to a report from Menniti, investigators kept digging and determined the package was actually sent by another man, named David Smith. He had been a senior employee at Mandrake but was dismissed in 2011 for allegedly misappropriating client information. Smith started a rival executive recruitment firm after he was let go from Mandrake and now pitches himself as the “headhunter of choice in the Toronto marketplace.”

The Perlmutters’ attorneys learned of Menniti’s report in May and claim that it’s proof they are innocent. Moreover, Perlmutter now alleges that Peerenboom was either complicit in or indifferent to Smith’s hate mail campaign, and ready to blame Perlmutter in order to extort a massive settlement. Peerenboom, for example, mused to the Globe and Mail last year he would “be prepared to let this slide” for $400 million.

The hate mail was designed to implicate Perlmutter from the start, the Perlmutters allege.“David Smith’s efforts were so clumsy they could only possibly fool someone—like Peerenboom—who either wanted to be fooled or was in on the act,” according to a court document. The use of Hebrew slang is a telling example, they argue: the expressions were lifted directly from a website, containing the same spelling and usage errors. Moreover, the Perlmutters claim that Peerenboom and the Kasowitz law firm likely knew about Smith’s alleged involvement, but they persisted in “publicly smearing” the Perlmutters. (No hard evidence has been provided for these claims.)

Kasowitz’s firm contends the information about Smith “basically proves nothing at all.” Peerenboom is emboldened by an entirely different revelation: Perlmutter recently admitted that in 2011, he and Laura directed a personal assistant at Marvel to research Peerenboom. (An email sent by Laura had the subject line “TROUBLE MAKER IN THE TOWNHOUSE.”) The assistant returned a few unflattering news articles, which Perlmutter sent along to friends. He also anonymously mailed copies to members of a country club where the Perlmutters and Peerenboom belonged. Perlmutter says he wanted to learn more about this recent Sloan’s Curve arrival and was troubled by what he found. Peerenboom claims this amounts to a “confession” linking the Perlmutters to the hate mail campaign. His attorneys only learned of this after suing Marvel in New York for access to Perlmutter’s email accounts.

The Palm Beach Police Department, meanwhile, suspended its investigation in May. On June 21, Toronto police arrested and charged David Smith with personation, uttering forged documents, criminal harassment and extortion. (The police will not say whether the charges relate to the hate mail.) Smith referred questions to his lawyer, who declined to comment. None of the allegations have been proven in court.

A resolution still looks to be a long way off. There are multiple lawsuits before the courts. Donnelly dropped her defamation case in 2014 before it went to trial, and Peerenboom then sued her, Perlmutter and Raphael for malicious prosecution, alleging the lawsuit was baseless. He’s also suing the Sloan’s Curve Homeowners’ Association for its handling of the tennis contract. Raphael, whom Peerenboom initially named as a defendant in the hate mail suit before dropping him, is suing for malicious prosecution.

Throughout all the turmoil, life goes on at Sloan’s Curve. Donnelly can still be found on the tennis court, and recently posted a Facebook video of her coaching a group of elderly but spry women. (“Never stop moving!!” she wrote.) Matheson still sells luxury properties. Earlier this year, she listed a townhouse at Sloan’s Curve for $4.7 million. The new owner will enjoy easy access to the beach and a world-class tennis centre, three doors down from Harold Peerenboom.