Last year, with the federal government making available huge new sums of money for programs to feed needy children during the pandemic, a nonprofit organization called Advance Youth Athletic Development set up what it described as an enormous child care operation in northeast Minneapolis that could prepare 5,000 dinners each weeknight.

Based on the group’s claims, the State of Minnesota channeled $3.2 million of the federal food aid to the program.

But on a subzero morning in January, the F.B.I. carried out a series of predawn raids around the region. It revealed a sprawling investigation into Advance Youth Athletic Development and other groups like it — and the much larger nonprofit organization, Feeding Our Future, that was responsible for ensuring that the money provided to the smaller groups was spent properly.

In court filings, the F.B.I. said it had discovered a “massive fraud scheme” among groups that Feeding Our Future was supposed to oversee, saying they siphoned off tens of millions of dollars by charging taxpayers for nonexistent meals.

In affidavits filed in federal court, the Justice Department said it was investigating at least 15 different feeding operations. Together, the F.B.I. said, these groups — all of which were supposed to be overseen by Feeding Our Future — had received more than $65 million from federal food programs during the coronavirus pandemic.

“Almost none of this money was used to feed children,” the government wrote in one filing. “Instead, conspirators misappropriated the money and used it to purchase real estate, cars and other items.”

When a reporter recently visited the address listed for Advance Youth Athletic Development, there was no sign of a kitchen or a large child care facility. It was a second-story apartment.

“No. No. No,” said Lul Mohamoud, a neighbor in the apartment across the hall, when asked if she had ever seen 5,000 children there. “I have never seen any kids going in there.”

No one has yet been charged in the case, and the leaders of Feeding Our Future, Advance Youth Athletic Development and other nonprofit groups have denied wrongdoing.

But the case has highlighted how the government’s reliance on nonprofits to help carry out an array of programs can increase vulnerability to fraud — a problem that only increased over the past several years, as Washington pumped trillions of dollars into pandemic aid packages.

That aid has focused new attention on the role of nonprofits in particular in acting as conduits and overseers of federal money that flows through them via the states and then to smaller organizations that carry out programs. States and the federal government count on groups like Feeding Our Future to guard against corruption — even as the system incentivizes the organizations to push more money out the door by giving them a cut of it.

In his State of the Union address last week, President Biden said that “billions” in pandemic aid had been stolen, and that he would soon name a chief prosecutor for pandemic fraud.

In Minnesota, state regulators said that even after they grew suspicious of Feeding Our Future, they had been constrained by the courts from stopping the organization. In fact, the state paid the group more than $197 million after the first suspicions were raised.

“The scale of this, and the rapidity of it, is astonishing,” said State Senator Roger C. Chamberlain, a Minnesota Republican whose committee oversees the food programs. He said his goal was to understand “why this system failed and collapsed completely. Because it certainly did.”

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The Minnesota case involves two multibillion-dollar federal food-aid programs, both funded by the Agriculture Department but administered by states. One pays for meals at preschools, emergency shelters and aftercare centers. The other pays for meals at summer activities.

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Since the F.B.I. raids, news coverage by The Star-Tribune and Sahan Journal, a local nonprofit media outlet, has revealed that some of the operators of Feeding Our Future sites had criminal records, and that a former top aide to Mayor Jacob Frey of Minneapolis, a Democrat, was among those under investigation. {snip}

Minnesota first approved Feeding Our Future as a sponsor in 2018. In its first years, the group oversaw only a few feeding sites — and, at times, seemed to struggle with overseeing itself.

In February 2020, for instance, the I.R.S. revoked the group’s nonprofit status after it failed to file an annual report for three years. (After this story was published, the I.R.S., which had earlier listed the group’s status as revoked, updated its website to reflect that it had reinstated Feeding Our Future’s tax-exempt status as of December.)

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From 2019 to 2021, the number of children in Feeding Our Future’s network increased to about 400,000, from about 4,000, according to state records. The revenue flowing through its network increased to $197 million from $3.5 million.

Feeding Our Future’s share grew to about $19 million, which its founder and president, Aimee Bock, said she spent largely on salaries for her 80 employees and supplies for feeding sites. She said she paid herself $190,000.

But there were puzzling features at some of the group’s new sites. In Minneapolis, two Feeding Our Future locations claimed to be running large child care centers out of the same small building — one feeding 2,000 children a day, the other 500, according to state records. (Ms. Bock said the state records were wrong, and she had never claimed that food was served there.)

Another operation, housed in the nearby Safari Restaurant, claimed to be feeding 6,000 children a day on its own — more than the total number of children living in the restaurant’s ZIP code. Ms. Bock said the children came from surrounding areas, because the food was appropriate for East African immigrants, many of whom live in the area.

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