Five months after a sweeping immigration raid at the Michael Bianco Inc. plant in New Bedford, company president Francesco Insolia and two of his top managers have been indicted on charges of conspiring to harbor and hire illegal immigrants, to fulfill almost $230 million in government contracts.

U.S. Attorney Michael J. Sullivan said the indictment “should send a clear message to all employers that hiring illegal or unauthorized aliens, or conspiring to shield them from detection, will not be tolerated.”

Sullivan, the U.S. Attorney for Massachusetts, said the alleged conduct by Insolia and his managers “undermines the integrity of our immigration system and could place legally operating businesses at a competitive disadvantage.”

Insolia and the other two defendants will be arraigned Aug. 9.

Insolia, of Pembroke, Mass., had no comment yesterday. He remained on the job, according to a spokesman.

The indictment was announced Thursday by Sullivan and Bruce M. Foucart, special agent in charge for the U.S. Immigration and Customs Enforcement office of investigations in Boston.

The Bianco company, which produces rucksacks and other military gear for U.S. soldiers in Iraq and Afghanistan, is operating on a reduced production schedule agreed to by the Department of Defense, said spokesman Doug Bailey, of Rasky Baerlein Strategic Communications of Boston.

The two-count indictment names Insolia, 50; production manager Dilia Costa, 55, of New Bedford; and contracts specialist Gloria Melo, 41, of Fall River. They are each charged with conspiring to harbor or conceal or shield illegal aliens from detection, or to encourage and induce aliens to come to, enter and reside in the United States; and with conspiring to hire and continue to employ unauthorized aliens.

A third manager, Ana Figueroa, who was charged in March after the raid, was not named in the indictment.

If convicted of the charge of conspiring to hire illegal aliens, Insolia, Costa and Melo each face maximum sentences of 10 years in prison, a $250,000 fine and a $100 special assessment, plus at least two years of supervised release. They face months in prison, a $100 special assessment, and a $10,000 fine for each illegal alien hired by the Bianco company on the charge of conspiracy to hire illegal aliens.

The indictment stems from an ongoing investigation that started last year and culminated with a March 6 raid at the plant at 89 West Rodney French Blvd., during which 361 illegal immigrants were detained.

The raid sparked widespread community outrage. Social service agencies, immigrant advocacy groups and public officials decried a “humanitarian crisis” that disrupted the lives of families.

After the raid, workers accused Insolia and his managers of maintaining “sweatshop” conditions referenced in the affidavit. They said Insolia fined workers $25 for arriving more than a minute late, or staying too long in the restrooms, and charged them for aspirin. They also said that the front door was the sole entrance and exit.

Last month, the Bianco company agreed to pay a reduced fine of $37,500 after the federal Occupational Safety and Health Administration cited the company for 15 alleged serious violations of workplace health and safety standards, including mechanical, electrical and chemical violations.

Left uncorrected, those conditions expose employees to the hazards of lacerations, amputation, burns, electrocution, eye and face injuries and to being caught in moving machine parts or struck by machinery, said Robert B. Hooper, OSHA’s acting area director for Southeastern Massachusetts.

Bailey, the Bianco spokesman, said OSHA reduced the proposed $45,000 fine after the company remedied the conditions cited in the inspection.

ICE is continuing its investigation with assistance from the Social Security Administration’s Office of Inspector General; the Department of Defense’s Criminal Investigative Service; the U.S. Department of Labor’s Office of Inspector General; the Massachusetts Insurance Fraud Bureau and the U.S. Postal Inspection Service.

kziner@projo.com