Koch Foods of Mississippi says the federal government illegally searched its chicken processing plant during an immigration raid and any evidence collected should not be used against the company.

The company claims the government's search warrant affidavit for its Morton plant was based on suspicion, not the legally-required standard of probable cause. While the affidavit says Koch Foods "willfully and unlawfully" employed undocumented immigrants, company attorneys argue the document doesn't contain "any evidence" to back that up.

U.S. Immigration and Customs Enforcement agents arrested 680 people on Aug. 7 during seven food processing plant raids in Mississippi. No charges have been brought against the four companies or their officials, but authorities have indicated that is likely.

Agents arrested 243 employees at Koch's Morton plant alone, more than at any other facility. They also seized company documents and other electronic data during the raids.

"If this search is allowed to stand, lawful businesses across the nation who legally hire immigrants are exposed to illegal searches founded on suspicion rather than probable cause," Koch attorney Michael Dawkins said in a motion filed Friday in U.S. District Court in Jackson.

Southern District of Mississippi U.S. Attorney Mike Hurst declined to comment about Koch's motion. ICE spokesman Bryan Cox said his agency had "lawfully executed federal criminal search warrants signed by a judge."

The company wants property taken from its plant during the raid be returned. It said while the government's search warrant affidavit suggests undocumented immigrants have worked at the plant, that doesn't demonstrate Koch Foods knew it was hiring them.

Federal law states that companies proven to engage in a "pattern and practice" of knowingly hiring undocumented immigrants can face fines, while company officials can face prison time.

The search warrant affidavit states that over a 17-year period, ICE encountered about 144 undocumented immigrants who told officials they had been employed by Koch Foods in Mississippi. It says that a government tip line received "numerous" leads that Koch was "knowingly hiring and employing illegal aliens." And it mentions evidence that 21 Koch employees were wearing ankle monitors as they awaited immigration hearings.

But this is not evidence indicating Koch Foods has been "knowingly hiring and employing illegal aliens," according to the company's filing. Koch Foods hired thousands of people in recent years, the filing states, so 144 is "statistically insignificant." And there are no claims in the affidavit that the tips to law enforcement produced "credible evidence" of Koch's wrongdoing.

The company also accuses the government of a "baseless and discriminatory assumption" that all Hispanic workers who wear ankle monitors are undocumented. It suggests workers could have instead worn them following other types of criminal justice proceedings, and that they are not always visible anyway.

In addition, Koch claims it cooperated in 2008 with a federal investigation into its hiring practices, turning over numerous employment documents. The company claims several employees reviewed in 2008 by the feds continued to work at the plant — and were arrested in the recent raids, with two recently being indicted for using fake identification documents.

"Apparently ICE reviewed this employee information in 2008 and, like Koch Foods, did not detect that some of these employees were using aliases," the motion states.

Matt Steffey, a Mississippi College law professor, said it is unusual but not unprecedented that a company would file such a civil motion before any criminal charges are filed.

"It's an indication of a very aggressive defense at a corporate level," he said of Koch's effort suppress evidence. "And it's typical in a broader sense of management trying to absolve itself of responsibility for hiring undocumented workers."

He said the government is likely to respond by saying the motion is premature, and ask a judge to either deny the motion or decline to rule on it until charges are filed. The government, he said, must only have probable cause to believe they will find evidence Koch knew it was hiring undocumented immigrants. "They don't have to prove the crime at the beginning of the investigation."

Steffey said if a judge ultimately decided the Koch search was illegal and evidence had to be suppressed, it would not necessarily affect the ongoing cases of the employees arrested during the raid.

The privately-held Koch, among the largest poultry processors in the U.S., is based in Chicago and churns out more than 700,000 tons of chicken annually from its Morton facility.

More:He fought for workers arrested in Arpaio's raids. Now Phoenix attorney is battling for workers arrested in Mississippi ICE roundup

Contact Jimmie E. Gates at 601-961-7212 or jgates@gannett.com. Follow @jgatesnews on Twitter.