MINNEAPOLIS (AP) — Federal Homeland Security officials were conducting a fraud investigation on Monday in Minneapolis, Department of Homeland Security Secretary Kristi Noem said.

The action comes after years of investigation that began with the $300 million scheme at the nonprofit Feeding Our Future, for which 57 defendants in Minnesota have been convicted. Prosecutors said the organization was at the center of the country’s largest COVID-19-related fraud scam, when defendants exploited a state-run, federally funded program intended to provide food for children.

A federal prosecutor alleged earlier in December that half or more of the roughly $18 billion in federal funds that supported 14 programs in Minnesota since 2018 may have been stolen.

Minnesota Gov. Tim Walz said then that fraud will not be tolerated and that his administration “will continue to work with federal partners to ensure fraud is stopped and fraudsters are caught.”

Noem on Monday posted a video on the social platform X showing DHS officers going into an unidentified business and questioning the person working behind the counter. Noem said that officers were “conducting a massive investigation on childcare and other rampant fraud.”

“The American people deserve answers on how their taxpayer money is being used and ARRESTS when abuse is found,” U.S. Immigration and Custom Enforcement posted.

The action comes a day after FBI Director Kash Patel said on X that the agency had “surged personnel and investigative resources to Minnesota to dismantle large-scale fraud schemes exploiting federal programs.”

Patel said that previous fraud arrests in Minnesota were “just the tip of a very large iceberg.”

President Donald Trump has criticized Walz’s administration over the fraud cases to date.

In recent weeks, tensions have been high between state and federal enforcement in the area as the Trump administration’s immigration crackdown focused on the Somali community in the Minneapolis-St. Paul area, which is the largest in the country.

Among those running schemes to get funds for child nutrition, housing services and autism programs, 82 of the 92 defendants are Somali Americans, according to the U.S. Attorney’s Office for Minnesota.

Walz spokesperson Claire Lancaster said that the governor has worked for years to “crack down on fraud” and was seeking more authority from the Legislature to take aggressive action. Walz has supported criminal prosecutions and taken a number of other steps, including strengthening oversight and hiring an outside firm to audit payments to high-risk programs, Lancaster said.