It is a rule universally acknowledged in crime writing that if you stash your ill-gotten gains under the mattress, someone is eventually going to find it. Just like the $20 million in cash hidden in a box spring that federal agents found in Massachusetts this week.

The U.S. Attorney’s Office in Massachusetts says the cash was seized on Monday, and a Brazilian man was arrested and accused of conspiring to launder proceeds of a massive alleged pyramid scheme.

He was charged with one count of conspiring to commit money laundering related to the alleged TelexFree pyramid scheme: the company purportedly sold VOIP telephone service, but prosecutors said instead it made most of its revenue from people buying into the company with promised payouts for posting online ads. Those folks were then allegedly paid with money from new recruits.

Back in April 2014, federal investigators searched TelexFree’s headquarters in Marlborough, MA. One of the founders of the company allegedly fled to his native country of Brazil and remained there, investigators say. He and the company’s co-founder were indicted in July 2014 on charges that they operated TelexFree as a massive pyramid scheme. The co-founder pleaded guilty to those charges in Oct. 2016 and is awaiting sentencing.

In the meantime, prosecutors claim that the other founder had an intermediary working on his behalf who contacted an associate for help transferring millions of dollars of TelexFree money hidden in the Boston area to Brazil.

That associate then became a cooperating witness for the government, and allegedly arranged to launder the cash through Hong Kong, convert it to Brazilian reals, and then transfer it to Brazilian accounts. According to court documents, the accused intermediary flew from Brazil to New York City a few days ago. On Sunday, he met with the cooperating witness and allegedly gave him $2.2 million in a suitcase. Agents followed the man and the suitcase back to an apartment complex and later arrested him. They later searched an apartment at the complex and seize the massive stockpile of cash.

Hey, now seems like a good time to brush up on the basics of a pyramid scheme! First of all, it’s illegal. And unlike a legitimate multi-level marketing plan, where the money you earn for participating is based on sales to the public, your income is based mainly on the number of people you recruit, the Federal Trade Commission notes, and the money those new recruits pay to join the company.

It’s worth noting that while multi-level marketing campaigns are legal, John Oliver, for one, is not a fan.

Although the alleged TelexFree pyramid scheme was originally aimed at Brazilian immigrants in Massachusetts, authorities allege that almost one million people around the world were swindled out of nearly $1.8 billion. That’s a lot to hide in box springs.

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