Charleroi has become a flash point in the presidential campaign, with former President Donald Trump saying Haitians are "invading" the Washington County town.Action News Investigates has learned federal authorities are investigating a company that supplies immigrant workers to a major Charleroi employer.Fourth Street Foods in Charleroi makes prepared meals that are sold in grocery stores across the country.It employs 700 immigrants from 41 countries, many of them Haitians.Getro Bernabe, a Haitian immigrant who used to work at Fourth Street Foods, is now Charleroi's liaison with the Haitian community.He said the immigrants at Fourth Street "work legally. They have their work permit. They have everything."Many of Fourth Street's workers are actually employed by a contractor, Prosperity Services. Prosperity also transports workers in vans, which can be seen throughout Charleroi.In court records, federal investigators said Prosperity "knowingly paid undocumented non-citizen employees with cash" and "transported and housed undocumented non-citizens for employment purposes."Earlier this year, the feds seized nearly $1 million in cash from Prosperity and two men affiliated with the company, including Andy Ha, the company president.One of the seizures occurred outside a building on Route 88 in Charleroi, where undocumented workers received cash payments from Prosperity, according to court records. The building was called "Pay Now.""I don't know anything about it," said Fourth Street Foods owner David Barbe.He said contracts with Prosperity and other labor agencies require them to hire only legal immigrants."The federal government has asked us questions, asked us to provide documentation, and we've done everything that they've asked for," Barbe said.Court records said Prosperity was headquartered at Ha's Belle Vernon home. When Action News Investigates went to the house, a current resident said Ha was no longer living there.When reached by phone and asked about the investigation, Ha hung up. His attorney did not return multiple voicemail messages.In August, the U.S. Attorney's office agreed to delay the civil forfeiture proceeding against Ha "until the conclusion of the related criminal investigation."A spokesperson for the U.S. Attorney's Office declined to comment.Amos Zougar, a Liberian immigrant who is now a manager at Fourth Street Foods, said he previously worked for Prosperity. He said he is legally in the United States."I want everybody to understand this: every single individual, every single immigrant that lives in Charleroi that works at Fourth Street Foods, they are legal," Zougar said.