"These employees are not in our payroll system therefore not being paid from the US and not paying U.S. taxes," the employee wrote, adding that "they are being provided fraudulent invitation letters verifying they are coming to the U.S. for business meetings and/or training."

Kenneth Mendelsohn, Palmer's attorney, also submitted an affidavit from a former employee at Johnson Controls, a customer site, which makes similar allegations about misuse. An email in June, 2011, claimed employees were working at this customer site on B-1 visas.

Mendelsohn said this employee confirmed that these workers "were coming here just to do regular work, which is illegal in a bunch of ways: Number one, it is displacing American workers, and number two, is they are coming over here on business visas" which don't allow work."

Infosys, in SEC filings, has stated that it and employees are targets of a federal investigation. The company has denied any wrongdoing, and it reiterated this in a statement Thursday.

"Our position is the same now as it has been from the beginning: We have not retaliated against any employee for bringing any suspected incident to the company's attention," a company spokesperson said in a statement. "We look forward to addressing this matter in open court in August, not in public venues where facts can become mixed with rumor, opinion and speculation."