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April 5 of last year began like any other day for Martha Pulido. But after arriving at her job in a meatpacking plant near Morristown in East Tennessee, she suddenly heard officers yelling at workers to put up their hands, she said.

“From one moment to the next, the plant turned to chaos,” Pulido said in Spanish. Immigration officers yelled and dashed throughout the plant, she said. She could hear helicopters.

At the time, it was the largest work-site raid by Immigration and Customs Enforcement in nearly a decade, with nearly 100 workers taken into custody on suspicion of being in the country illegally.

On Thursday, two advocacy groups and a law firm filed a lawsuit against immigration officers, accusing them of unlawful searches and arrests, racial profiling and excessive force.

"When a raid of this scale happens in our communities, it's like a bomb goes off," Stephanie Teatro, executive co-director of the Tennessee Immigrant and Refugee Rights Coalition, said during a news teleconference Thursday announcing the lawsuit.

Attorneys said it was the first lawsuit against a large-scale work-site raid conducted by the Trump administration.

In the aftermath of the raid, hundreds of people gathered at a church, desperately trying to find their family members, and nearly 600 children from the district missed school.

"As the tragedy and chaos unfolded on that day, it was a painful reminder of why the government had stopped using this egregious enforcement tactic almost a decade before," Teatro said.

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Pulido said one of her co-workers slipped and fell, and immigration officers “drew their guns at her.” She said she saw one officer hit an employee in the face and another push a colleague.

Martha Pulido Isaias Guerrero

“Why the excessive use of arms and violence? The only thing we were doing was making a living to support our families,” she said.

The suit was filed in federal court in Knoxville by the National Immigration Law Center, the Southern Poverty Law Center, and the law firm of Sherrard, Roe, Voigt and Harbison on behalf of seven named workers and about 100 unnamed ones who were detained during the raid. The suit, which names nine federal officials and includes 30 unnamed ICE agents, claims the workers' rights were violated and seeks monetary and punitive damages.

Meredith Stewart, a senior supervising attorney at the Southern Poverty Law Center, said what happened during the raid was illegal.

“ICE agents stormed the meatpacking plant looking for Latino workers without knowing their identities or immigration status,” she said. “They detained those workers solely on the basis of their race, using intrusive, militaristic and even violent measures. This is law enforcement overreach, plain and simple.”

Melissa Keaney, a staff attorney with the National Immigration Law Center, said ICE officers were at the meatpacking plant, Southeastern Provision in Bean Station, that day with a search warrant for financial documents for alleged crimes by the plant’s owner.

“But clearly, their purpose that day and intent was far broader than what the warrant itself authorized,” Keaney said.

An ICE spokesperson told NBC News it does not comment on pending litigation, but that, in general, "ICE activities are conducted in full compliance with federal law and agency policy."

The spokesperson said ICE's Homeland Security Investigations division "equally focused" enforcement efforts on employers who knowingly hire unauthorized workers as well as those employees.

"The Southeastern Provision case was always a federal criminal investigation that also resulted in administrative immigration arrests," the spokesperson said. "To describe the operation as an immigration enforcement action is inaccurate; it was a federal criminal investigation that also resulted in immigration arrests."

At the time of the raid, ICE said that of the 97 people detained, 86 were arrested on administrative charges and placed in deportation proceedings, with 54 placed in detention centers and 32 being released.

Since then, advocates said Thursday that 40 have been released on bond, five remain in federal custody, six have been deported and 12 agreed to voluntary departure, in which an immigrant agrees to leave the country rather than go through a formal deportation process.

Attorneys on Thursday declined to discuss the immigration status of the plaintiffs at the time of the raid, saying they did not believe it was relevant to the claims in the lawsuit and alleging that ICE agents used race as a proxy for determining workers' suspected immigration status.

The Tennessee raid was followed by a pattern of other large workplace raids — at least one, in Ohio, was larger — after the Trump administration's pledge to step up arrests at companies accused of employing immigrants who are not authorized to work in the United States.

The owner of the meatpacking plant, James Brantley, pleaded guilty in September to federal charges of tax fraud, wire fraud and hiring immigrants unauthorized to work in the country and is awaiting sentencing, according to ICE.