Arresting 147, a federal law enforcement operation — one of the largest in Homeland Security Investigations’ 15-year history — targeted Midwestern businesses that officials say knowingly hired — and mistreated — illegal immigrants.

The focus of the operation was unusual in that it targeted business operators for arrest. Most immigration raids have targeted workers suspected of being in the country illegally.

“The whole investigation was initiated, basically, because we knew that these businesses were cheating these workers and cheating taxpayers and cheating their competition,” Special Agent in Charge Tracy J. Cormier, HSI St. Paul, which oversees Nebraska and Minnesota, said.

The investigative arm of U.S. Immigrations and Customs Enforcement — Homeland Security Investigations — led the operation in Nebraska and Minnesota that saw about a dozen businesses and plants raided and 17 business owners and managers indicted for fraud, wire fraud and money laundering.

Of those, 14 were taken into custody Wednesday and three were still being sought. Authorities also arrested more than 130 workers at various businesses, busing them to Grand Island, Nebraska, to be questioned and processed.

“The job magnet in the United States is primarily what draws illegal aliens across our borders,” said Cormier in a statement posted to ICE’s website. “This HSI-led criminal investigation has shown that these targeted businesses were knowingly hiring illegal workers to unlawfully line their own pockets by cheating the workers, cheating the taxpayers, and cheating their business competitors.”

The businesses engaged in a scheme that used fraudulent names and Social Security numbers to employ people in the country illegally, she said. The businesses used “force, fraud, coercion, threat of arrest and/or deportation” to exploit the workers, Cormier said. The business that hired out the immigrants also forced the workers to cash their paychecks with that business for an exorbitant fee, officials said, and withheld taxes from workers’ pay without paying those taxes to the government.

“It kind of reminds us of the revival of the old ‘company store’ policy, where it used to keep the coal miners indebted to the company for all kinds of services ... like check cashing,” she said.

Between 350 and 400 federal, state and local law enforcement officers worked together on the arrests, Cormier said.

Most of the arrests took place in northern Nebraska and southern Minnesota.

Several of the businesses were in O’Neill, Nebraska, a town of about 3,000 about 160 miles northwest of Omaha. Officials said they were still looking to take three owners or managers into custody as part of the operation.

Also arrested were 133 workers suspected of being in the country illegally, according to ICE. Some will be issued notices to appear before an immigration judge and released, while those with criminal backgrounds will remain in ICE custody, officials said.

The raids come as President Trump’s administration has been carrying out high-profile immigration enforcement actions against employers.

Dozens of workers were arrested at a meatpacking plant in rural Tennessee in April, followed by agents rounding up more than 100 employees two months later at an Ohio gardening and landscaping company.

Immigration officials also have beefed up audits of companies to verify their employees are authorized to work in the country.

Officials opened nearly 5,300 employer audits since January, many after audits at 100 7-Eleven franchises in 17 states in January.

Pork producing giant Christensen Farms saw search warrants served at its headquarters in Sleepy Eye, Minnesota, its truck wash facility in Appleton, Minnesota and a producer plant in Atkinson, Nebraska. Spokeswoman Amber Portner said the company was cooperating with agents. She said she knew of no arrests at any of the company’s locations Wednesday.

Other businesses raided were in Stromsburg, Ainsworth, Bartlett and Royal, all in Nebraska.

Civil rights organizations in Nebraska were quick to denounce Wednesday’s operation.

“The ACLU condemns this ongoing campaign of misery that targets immigrants, disrupts local businesses and separates families,” Rose Godinez, an attorney with the American Civil Liberties Union of Nebraska, said in a written statement released Wednesday morning.

The effect of such operations are the same whether they target businesses or immigrants, said Jeff Sheldon, spokesman for advocacy group Nebraska Appleseed.

“This is going to leave widespread fear and damage in the community,” he said. “You got businesses that are directly affected. You’ve got neighborhoods that are directly affected. You’ll have kids tonight coming home to a house where one or more of their parents are gone. This is pain that can last for generations.”

The Associated Press contributed to this report.