Jerry Jacobson swindled more than $24 million out of a major fast food promotion over 12 years. His trick: stealing and selling McDonald’s Monopoly game pieces.

Jacobson’s fortune, and his downfall, came from gaming the twice-a-year promotion, which promised anything from a free sandwich to $1 million to the customer who revealed the lucky game piece — a property, a railroad — when they peeled off the sticker attached to their hash brown wrapper or soda cup or the inside of a magazine.

He was in charge of keeping the promotion secure, delivering the most lucrative game pieces to McDonald’s packaging plants. Instead, through most of the 1990s, he pocketed and sold them to a vast network of friends and distant relatives. In the end, more than 50 people were convicted in the scheme.

“McMillions,” a six-part HBO documentary series premiering Monday, chronicles the scam and its unraveling. Here’s what to know before you watch.

Who was involved?

It was Jacobson who watched the winning pieces being printed, who locked them away in a vault, who sealed them up and tucked them in his vest and flew from factory to factory to hide them in McDonald’s packaging, according to The Daily Beast, which looked back on the case years later.

Jacobson went into private security work after having served briefly as a police officer in Hollywood, Florida. His connection to the Monopoly game began when he and his wife at the time, Marsha, moved to Atlanta, where she began work as a security auditor. She helped her husband get a job with one of her clients, Dittler Brothers, which printed the McDonald’s game pieces. He later moved to Simon Marketing, a company in the same area, that produced the pieces.

Soon, he started slipping the prize-winning pieces to people he knew, sometimes for profit. His stepbrother. His local butcher, who paid $2,000 for a stolen $10,000 piece. His nephew, who received a $200,000 piece in exchange for $45,000.

Over the years, the fraud grew beyond his circle as he found other conspirators, usually by chance — which made them more difficult to pin down during the FBI’s investigation years later. Jacobson, according to The Daily Beast story, said he met Gennaro Colombo, who claimed to be a member of New York’s Colombo crime family, at the Atlanta airport in 1995. Jacobson was waiting to board a cruise ship several years later when he met Don Hart, who in turn introduced him to Andrew Glomb at a dinner party. They became Jacobson’s accomplices, the middlemen who would sell the pieces Jacobson had swiped to various “winners.”

How did it work?

Jacobson came across the materials he needed by accident, according to The Daily Beast article. A supplier sent him a package by mistake, filled with the metallic tamper-proof seals — the ones used to secure the envelopes filled with game pieces that Jacobson was charged with delivering.

In airport bathrooms — en route to packaging plants — Jacobson would remove the envelope’s original seal, swap out winning pieces for regular ones and resecure the envelope with one of the new seals he was sent.

He would then pass the winning pieces on to Colombo and his other “recruiters,” who tracked down willing buyers and coached them through claiming their winnings. Colombo sold a $1 million piece to Gloria Brown, a friend of his wife, on the side of the highway for $40,000 in cash, Brown said in an interview with The Daily Beast. He then drove her to a McDonald’s, walked her through what to say and helped her lie about where she lived to avoid drawing suspicion — a surplus of winners was popping up in Jacksonville, Florida, where she and others connected to Colombo resided.

How were they caught?

In March 2000, according to The Daily Beast, the FBI received an anonymous phone tip: Someone named “Uncle Jerry” was rigging the McDonald’s Monopoly promotion, stealing game pieces from the inside and selling them.

Special Agent Richard Dent, based in the FBI’s Jacksonville office, contacted a McDonald’s spokeswoman, Amy Murray, who began trying to verify the winners. One winner — Colombo’s father-in-law, who claimed $1 million from the contest — told Murray that he lived in New Hampshire, but property records in Jacksonville proved otherwise. Gloria Brown, Murray found, was also having her annual checks delivered to a Jacksonville address.

Dent launched an investigation that would rope in 25 agents nationwide. He found his big lead in 2001, when he mapped out the addresses of three winners — all of whom lived within miles of Jacobson’s South Carolina lake house.

Dent convinced McDonald’s to run one more Monopoly promotion, so the FBI could track down the final evidence it needed. The move was fraught with legal risks — the corporation, in its collaboration with federal investigators, already knew at this point that its game was compromised.

The decision paid off, allowing Dent to pin down Andrew Glomb for the first time. Colombo, though, died after a car accident in 1998. The FBI arrested eight major suspects on Aug. 22, 2001, and charged Jacobson with conspiracy to commit mail fraud.

What’s happened since?

There’s a reason the scheme didn’t last long in the public’s memory: The trial, in Jacksonville, started on Sept. 10, 2001, and was quickly overshadowed by the events of Sept. 11.

Jacobson, who declined to speak to The Daily Beast and did not respond to a request from The Times, said at his trial that he had stolen as many as 60 game pieces. He served 37 months behind bars and agreed to pay $12.5 million in restitution. Now in his late 70s, he still lives in Georgia.

McDonald’s, through an instant million-dollar giveaway, tried to quietly make amends with customers.

It was not the first time, or the last, that someone had gamed a competition supposedly decided by luck. In 1998, several years before Jacobson’s trial, an agent with Nevada’s Gaming Control Board was sentenced on a racketeering charge after designing a computer program that rigged slot machines in Las Vegas, Reno and Lake Tahoe.

And in 2010, the director of information security at the Multi-State Lottery Association, which runs the game in 33 states, wrote a computer code to manipulate the association’s random-number generators — producing winning lottery numbers that he could predict in advance.

McDonald’s still runs similar promotions to the Monopoly sweepstakes, but the corporation has since created an “independent promotions task force” to prevent future copycats.