In less than a decade, the Jaafar family of Watertown managed to claim more than $20 million in lottery winnings from over 14,000 scratch tickets and other games — a stunning run of success that just didn’t add up.

An information technology expert at the lottery had run the math to show just how unlikely it was. An instant-win game called “$10,000,000 Big Money” had a 1 in 1,106.72 chance of producing a jackpot of $1,000 or more, he reported. Yet somehow, over a recent span of six months, the Jaafars had managed to claim nearly $2 million in winnings, the bulk of it from instant tickets like “$10,000,000 Big Money.” To win at that rate, the Jaafars would’ve had to purchase 22,859 such tickets every day, 952 tickets every hour, 16 tickets every minute. “Every minute of every day,” the official said. “Twenty-four hours a day.”

In lottery terminology, there was a name for this. The Jaafars were “high-frequency winners.” They were also breaking the law and the rules of the lottery itself by working with dozens of convenience store operators in an underground network where everyone was trying to avoid paying taxes on lottery prizes. In this network, everyone got cash under the table while the Jaafars got the winning tickets to claim as their own. A lot of them. In 2019 alone, the Jaafars claimed more than $3.2 million in winnings. Yousef was the sixth-highest ticket casher in the entire state that year, Mohamed was third, and their father topped the list.

It had all come to a head in recent months. The Lottery Commission had moved to suspend the Jaafars, the Jaafars had hired a lawyer, and everyone had landed in Suffolk County Superior Court, squabbling over the family’s right to play games for money.

But now, on a warm summer day in 2020, Yousef Jaafar was back. He was downstairs, with three winning tickets in his hand. The customer service agent was on the phone calling Dan O’Neil and O’Neil was on the elevator heading down to confront a man at the heart of what he now calls “the biggest money laundering operation that the lottery has seen.”

The conversation near the ticket windows did not go well. O’Neil informed Yousef that the lottery would not be cashing his tickets that day. Yousef, O’Neil recalls, became angry. He lashed out at the lottery, and seemed prepared to make a scene in the lobby because Yousef believed he was legally entitled to claim his jackpot. It was his business, the family business.

And if the whole thing looked curious, absurd, or even mathematically impossible, the Jaafars had a way of explaining it to make it sound plausible to people who didn’t know the odds, to people who didn’t understand the game.

The father told people that they were just lucky. The luckiest men in Massachusetts.

THE TALE OF THE JAAFARS — until the problems with the lottery — was best framed as an American success story. Ali was born in Lebanon in 1958 and had to overcome many troubles as a young man. His parents divorced. War broke out between heavily armed militias. Massacres on the streets became all too common, and sometime in 1975, just before Christian forces torched Muslim neighborhoods in Beirut, ultimately killing 1,500 people, Ali and his father made a choice: The boy wasn’t finishing high school in Lebanon. He was getting out.

Ali moved to live with his father — 3,500 miles away in Sierra Leone in West Africa — and for a time, he carved out a life for himself there, pious and gentle and, according to loved ones, hardworking. He met a young woman named Souraya. She knew immediately that she loved him. They married and had three children, and then, in the spring of 1991, Ali faced trouble again. Liberian rebels invaded Sierra Leone, throwing the country into chaos and forcing hundreds of thousands of people to flee.

For the second time in his life, Ali was looking to escape, and this time, Souraya was there to help. Her parents had somehow managed to immigrate to America a few years earlier. With their assistance, Souraya said later, she and Ali navigated the difficult process of obtaining US visas. They won what she described as “the visa lottery” and made their way to Massachusetts in 1992. A young family, safe at last.

They rented a home just off the interstate in Waltham, and in that moment, Ali felt grateful and looked for ways to give back. He saw himself as “a servant to Allah,” a relative later told the court, whose purpose was to help his community. And he seemed especially intent on helping his four children, including Mohamed and the new baby, Yousef.

As they all started over, Ali had just one goal in mind: “To provide for and give his children the best life growing up,” a relative said. “Everything that they needed to succeed in America.”

It wasn’t easy. Ali was in his mid-30s when he landed in Massachusetts. He had no high school diploma. He spoke limited English and had few job prospects. With most doors closed to him in his new country, Ali found employment at a service station pumping gas.

To put food on the table, Ali worked long hours. “Hardly ever spending time at home,” Souraya observed later. But this wasn’t a complaint. Ali was working to support the family, anything for the family. Even when Ali was pumping gas, the Jaafars didn’t want for anything. Eventually, he saved up enough money to buy a taxi — Jaafar Cab Inc. — and invested in a product that seemed to have potential: prepaid phone cards.

It was the 1990s and phone cards were in high demand, especially at convenience stores frequented by immigrants such as the Jaafars. Shopkeepers knew to summon Ali whenever they ran low on cards and he would show up in his taxi and deliver them by the stack. The side business was apparently profitable enough that Ali could stop driving his cab. He started a new company — Assorted Phone Cards — and used his money to finance an important purchase.

In the fall of 1997, the Jaafars bought a home in Watertown for $206,000. The street was lined with modest ranch-style homes, but a friend of the Jaafar children remembers thinking that their home was bigger than most he visited in town. It had two stories and four bedrooms. More importantly, the house ensured that the four Jaafar children would be educated. They could attend Watertown High School and earn the one thing that had eluded their father: a diploma.

To Souraya, it all felt like a dream. They had never quit, they had persevered, and now here they were with the house in Watertown, the children in school. She didn’t mind saying that she felt blessed, even lucky. “I always felt lucky,” she’d say later in a letter to a judge.

Her second son, Mohamed, certainly gave her no reason to feel otherwise. Mohamed had expressive eyes, a warm smile, and a studious nature that was apparent to everyone from the moment he walked through the doors at Watertown High in the fall of 2004. Classmates recall a boy who worked hard, earned National Honor Society accolades, joined the student government, played varsity soccer, and made sacrifices for his faith and his family that other students wouldn’t forget, even years later.

Ramadan requires Muslims to fast from sunrise to sunset for an entire month, and during Mohamed’s senior year, the holy month fell during September, soccer season. Teammates recall that it would have been easy for Mohamed to eat crackers before the games or sneak sips of water on the bench. “But he never did,” says teammate Bijan Ghom. Mohamed had discipline. “Unusual discipline,” Ghom adds, “for a high school kid.”

College admissions officers noticed. After high school graduation in 2008, Mohamed attended Northeastern University, where he earned a bachelor’s degree in international affairs. He then went on to collect a master’s in business administration at Bentley University while building an impressive résumé of work experiences. Mohamed spent a year assigned to a committee at the Massachusetts State House, interned for then-Senator John Kerry, and served as a research assistant for a Bentley professor writing a book. It was the work of an ambitious student who seemed interested in a career in public policy or politics. But at least one former classmate in Watertown speculated that Mohamed might end up working with his father instead.

According to his résumé, Mohamed joined the phone card business as soon as he graduated from high school, and quickly moved up from customer sales representative to operations manager. He expanded his father’s customer base by personally visiting convenience stores and said he offered the highest level of customer service through “honest business practices.”

It was an odd choice of words, given what Mohamed knew by that point. His father was no longer just selling phone cards: He was engaging in what Mohamed himself would later call “the lottery scheme.”

The Jaafars’ scheme was built on a premise that’s been known to gamblers for decades: Some people prefer not to publicly claim their winnings, particularly if they want to hide money from the Internal Revenue Service.

At American racetracks since at least the 1960s, these reluctant winners have turned to “ten percenters” for help. In the shadows beneath the grandstands, ten percenters would pay cash for someone’s winning ticket, minus a 10 percent cut off the top and often even more — 15 or 25 percent. The real winner would walk away with cash in hand, off the books, tax-free, while the ten percenter would claim the full prize at the racetrack window and often avoid taxes by claiming large gambling losses at the end of the year or by submitting fake identification at the track.

It usually amounted to tax evasion and could have devastating ramifications: the government sometimes lost as much as $1 million a week in tax revenue at a single track. It was only a matter of time before a similar practice of ten percenting infected state-run lotteries. For any jackpot over $600, winners have to produce a valid ID and Social Security number, and pay taxes. Those who owe back taxes or child support have one more obstacle to clear: Massachusetts authorities will take that money before paying out any winnings.

In this world, someone holding a scratch-off ticket worth $1,000 can sell their prize to a convenience store operator for $750 or $850. The winner leaves with cash under the table. The convenience store clerk picks up the phone and calls a runner. This person shows up and buys the ticket for the discount price, minus a cut for the clerk — maybe $50. The runner then pretends to be the real winner and claims the ticket at a lottery office for its full value, scoring a profit of $100 or $200.

It’s a black market that has existed in Massachusetts since at least the late 1990s, according to state audits. A 2002 investigation identified at least 58 high-frequency winners who had claimed a total of $4.7 million the previous year and paid minimal taxes. By 2004, this pool had grown to at least 88 people, claiming $10 million in all. And a 2010 report sounded the alarm about “professional ticket cashers” one more time. “Our follow-up review,” the state auditor declared, “disclosed that this practice is ongoing and has become even more widespread.” Sometimes, store employees even cashed the tickets themselves, skipping the runner entirely. In one instance, an employee walked into a lottery office in Braintree and cashed 14 winning tickets in a single day.

How Ali Jaafar started ten percenting, or why, isn’t clear. But as a man who visited convenience stores for a living — phone cards in hand, conversations in the candy aisle — he wouldn’t have had to work very hard to hear whispers about easy money. And sometime in 2011, when Yousef was graduating from Watertown High and headed to Suffolk University — and Mohamed was finishing his junior year at Northeastern — their father made a choice that would change the trajectory of their whole family.

He cashed a lottery ticket. And then another. And then some more. In 2011, according to lottery records, Ali claimed 136 tickets worth $217,000. The next year, he claimed 214 tickets totaling $367,000. In 2013, he blew these numbers away, claiming 867 tickets worth almost $1.3 million. Then he exceeded that figure every year for the next six years.

Every spring during this stretch, Ali listed gambling losses on his tax returns that allowed him to avoid paying taxes, despite lottery winnings approaching $10 million. Some ten percenters claim casino losses at tax time; some grab handfuls of losing scratch-off tickets from trash bins at convenience stores, then bundle them together to keep should the IRS come calling. According to testimony from an accountant who worked for Ali, the father didn’t produce any such records. The losses and winnings just seemed to cancel out. Ali’s lottery ticket business kept growing until it became the family business. In 2013, according to state records, Mohamed and Yousef started claiming tickets, too.

In federal court later, Mohamed agreed to a set of facts about how it all worked. When a convenience store operator had a winning ticket of more than $600, the operator would call the Jaafars. The father or one of the sons would show up to buy the winning ticket for an agreed-upon price less than the actual prize. Usually, they’d never learn the real winner’s name. That person disappeared with cash in hand, here and gone. The convenience store operator got paid — perhaps $50 for a small jackpot, $100 for something larger — and the Jaafars went to a lottery office to claim the full jackpot. Once there, one of the Jaafars signed the ticket, as required, and certified that he was the “sole recipient” of the prize and not working to “assist another in the avoidance of financial obligations.” Then sometimes they posed for photos like any ordinary winner.

Because the Jaafars purchased the tickets for 75 or 85 percent of their value, they weren’t pocketing the full jackpots. But the money did add up. A lawyer for Ali and Yousef admitted in court documents that the family made at least $2 million off the scheme. Their system also resulted in more than $6 million in federal tax losses, according to the US attorney’s office in Massachusetts, and earned the Jaafars themselves more than $1.2 million in tax refunds. “From tickets they never won,” one federal prosecutor said later, “based on gambling losses they didn’t actually have.”

Mohamed knew he was on what he called a “dark path.” He should have never participated in the scheme, he said, and he should have protected his younger brother, Yousef. If he were stronger, Mohamed said, he would have stood up to his father and saved them both, and he wondered what it said about him that he didn’t, that he couldn’t. Mohamed worried that he was “naïve and weak” — or worse. “Pathetic,” he said.

In 2016, Mohamed pleaded guilty to a conspiracy charge in New Jersey connected to an alleged overseas money-laundering operation and, at some point, sought psychological counseling for depression. Still, he continued buying winning lottery tickets — at convenience stores in Melrose, Worcester, Chelsea, Charlestown, and beyond. Mohamed didn’t want his father to see him as the “bad son,” he said, and he couldn’t overcome his father’s pressure — ”substantial psychological pressure,” Mohamed’s lawyer John F. Palmer called it. Mohamed couldn’t stop, even when he tried.

In 2017, according to Palmer, Mohamed informed his father that he was done — he was finished doing this work. Ali, a man who had once crossed continents for his family, allegedly responded by kicking his son out of the house in Watertown. Mohamed was only allowed to return, the lawyer said, if he agreed to keep claiming lottery tickets.

In the summer of 2017, The Boston Globe, in collaboration with other newspapers and Columbia University’s Graduate School of Journalism, exposed the practice of ten percenting in states across the country. Massachusetts was identified as the state with the biggest problem in the nation, which finally sparked the response that the state auditor had been calling for since 2002.

Michael R. Sweeney, the lottery’s executive director at the time, promised better oversight. Within months, the Lottery Commission adopted a new policy authorizing the director to suspend high-frequency winners for claiming tickets deemed to be “factually or statistically improbable.” The commission held hearings in May 2019 to investigate the Jaafars. It quickly moved to suspend all three of them, plus two other players. The Jaafars tried to fight the ruling in Suffolk County Superior Court that September — a fight that proved unsuccessful — and that same month Sweeney hired a new director of compliance and security: Dan O’Neil.

A longtime investigator for the state inspector general’s office, O’Neil, 53, has close-cropped hair, a tight beard that’s neatly trimmed, and a steady demeanor that was obvious even when he was a teenager growing up in Merrimack, New Hampshire. O’Neil played quarterback in high school, led Merrimack High to an undefeated season as a senior, and helped rally his squad from a 13-point deficit in the state title game to win the 1987 Division II championship.

After getting hired at the lottery, O’Neil didn’t even bother decorating his small, windowless office; even now, four years later, there’s almost nothing on his walls. Instead, he dove right in. He met with Sweeney to discuss the problem of high-frequency winners and left the meeting asking himself questions about the people trying to cheat the system.

“How are we going to suspend them — first and foremost? And then how are we going to determine whether or not there is a criminality involved and get the proper law enforcement agencies involved?” O’Neil recalled recently. “My first day — this was my directive. There were a couple internal issues that I had to deal with, but the overall, general issue facing the lottery — in Michael Sweeney’s eyes — was ten percenters and the integrity of the game.”

While O’Neil’s team of investigators began to mine the data on the Jaafars’ operation, including the stores where they seemed to secure the most tickets, the Jaafars got creative, too. By October 2019, Yousef had enlisted two friends to cash tickets for him at the lottery office, so that he wouldn’t have to show his face there anymore. The two men, Ahmed Shikhalard and Nicholas Frankel, testified later in court that they did what Yousef wanted on several occasions in exchange for $200, gas money, or a little food.

But Yousef’s plan involving his friends wasn’t nearly as creative as it needed to be. By then, the Internal Revenue Service was on the case, too. On two occasions, an undercover IRS agent sold winning tickets to a convenience store clerk in Somerville, and somehow, the agent testified later, these two tickets ended up in the hands of Shikhalard and Frankel, providing the government with a direct link to the Jaafars. Shikhalard and Frankel stopped doing Yousef’s work shortly thereafter; a lottery investigator had confronted one of them.

On June 26, 2020, Yousef returned to lottery headquarters with those three winning tickets in hand, according to state records. He had that strained and angry conversation in the lobby with O’Neil, and less than two weeks later Mohamed showed up as well, only to be turned away, just like his younger brother.

The discussion with Mohamed that day was quieter, O’Neil recalls, perhaps because Mohamed knew what was coming next. At the end of that summer, federal agents searched the Jaafars’ home and began to question other people involved: the convenience store operators and Yousef’s friends. Frankel testified later how Yousef showed up unannounced at his workplace that weekend to coach him on what to tell authorities, and he recalled specifically how that interaction ended: “With Yousef saying this conversation didn’t happen.”

But Frankel, a young father, newly married, had never felt good about his dealings with Yousef — and the lottery. He worked out an immunity agreement with the government and, within months, federal prosecutors indicted the Jaafars — Ali, Mohamed, and Yousef — for conspiracy to defraud the United States, conspiracy to commit money laundering, and multiple counts of filing false tax returns. They had become the most prolific ten percenters in Massachusetts.

The Jaafar trial last winter at the US District Court in Boston lasted five days. But it only involved Ali and Yousef. In November, about a month before the trial started, Mohamed agreed to cooperate with federal prosecutors, struck a deal, and pleaded guilty to a single conspiracy charge. Mohamed didn’t have to worry when both Shikhalard and Frankel testified against his father and brother. He wasn’t there when jurors took less than two hours to convict them on all counts, and Mohamed didn’t have to stand in the courtroom last May when the federal judge handed down stiff sentences to both of them. Ali got five years in prison, Yousef got a little over four, and the men were ordered to pay the IRS $6 million in restitution.

Ali and Yousef’s lawyer, Valerie S. Carter, objected to these sentences last spring. In an email to the Globe at the time, she said convenience store operators — working to recruit people like the Jaafars and skimming their own money off the top — were the “major wrongdoers” here. Her clients, she said, had been used.

But O’Neil points out that lottery investigators, state authorities, and federal prosecutors haven’t just focused on the Jaafars. They’ve gone after other ten percenters, their runners, their clients, a Boston police officer who sold a $10,000 ticket on the black market to dodge detection, and the convenience store operators who have worked with them behind the scenes. Last spring, the Lottery Commission moved to revoke or suspend sales licenses at more than 40 locations.

“We’re just going down the line,” O’Neil says, “and now we have the tools. We have the precedent.” His team, he says, also has the support of high-ranking state officials, including state Treasurer Deborah B. Goldberg, who oversees the Lottery Commission, and the lottery’s new executive director, Mark William Bracken. “Do we want to be suspending players? Do we want to be removing agent licenses from communities? No, that’s the last thing I want to do,” Bracken says. “But we take this seriously — in order to protect the integrity of our games and maintain the confidence of our player base.”

It’s a player base that is unlikely to ever include one man again: Mohamed Jaafar.

He faced his own sentencing in US District Court in late July. Despite the significance of the day, and everything that was at stake, the 33-year-old son of Ali and Souraya showed up alone. Mohamed wore a fitted gray suit for the occasion. He paced outside, hands in his pockets. He waited for the proceedings to start, and he declined to speak for this story, both that day and later. Outside of statements made in court documents, none of the Jaafars has ever talked publicly about what happened with the lottery.

But when given a chance to explain himself at his sentencing, Mohamed spoke to the judge and began to cry. He admitted that what had happened was more than just a mistake; it was a crime, Mohamed said — ”a very gross and disturbing type of crime.” He took responsibility for it. He apologized “for not being a better citizen.” He promised to make amends. “I just want to live a modest and peaceful life,” he said. And though he could have blamed his father for what had transpired, he didn’t. “The only person to blame for seriously ruining my own future is myself.”

Judge Nathaniel M. Gorton told Mohamed that he appreciated the sincerity of his statement. “But you do need to suffer the punishment of jail time,” Gorton said, “not only to deter you from ever committing a similar crime, but to deter anyone else, generally, who thinks this ten percenting is something that we are going to tolerate.” It isn’t, Gorton said, not anymore, and he believed that this sentiment was reflected in the sentence he was about to impose: six months in prison, with an order to pay $964,000 in restitution and a two-year ban on any activities related to the lottery.

“Do you understand that?” the judge asked Mohamed.

“Yes, your honor,” he replied.

The court adjourned and Mohamed gathered himself to leave, moving slowly and looking broken. The sentence was harsher than what his lawyer had requested.

But in the finality of the moment, Mohamed felt something that he admitted to the judge was a little strange, a little odd. He felt relief, a certain calmness. “It feels like a dark cloud has floated away,” he said, “and I can finally see a clear path.”

It was almost like he was lucky.

Keith O’Brien, a former Boston Globe reporter, is author of several books including the forthcoming Charlie Hustle: The Rise and Fall of Pete Rose, and the Last Glory Days of Baseball. Send comments to magazine@globe.com.