The Sterling steel manufacturing companies where 17 undocumented workers were arrested this month by the Immigration and Naturalization Service also are being investigated by a federal grand jury, according to the companies' attorney.

The arrests were made Nov. 3 when the FBI and the Defense Department's criminal investigative service executed a search warrant at Sibel Ayse Halac Iron Works Inc. and Halac Enterprises in Sterling. The INS was asked to participate after the FBI determined that foreign nationals were likely to be present, according to a statement released by the INS.

The FBI and Defense Department's investigative unit are examining both companies and their officers for possible criminal violations, the INS statement said. An FBI spokeswoman did not return calls seeking comment.

The companies' attorney, Stanley Reed, of Lerch, Early and Brewer in Bethesda, said he had not been told what the grand jury investigation was about.

"It's a grand jury investigation," Reed said. "At this stage, I'm not sure what it's about."

Marie Parker, a spokesman for the U.S. Attorney's Office in Alexandria, said she could neither confirm nor deny that an investigation was under way. The proceedings of grand jury investigations are secret, and the materials that are reviewed are unavailable for review by the public.

It was unclear when the grand jury investigating Halac would conclude its work. Grand jury investigations can last from a few weeks to several years.

Ahmet Halac, president of both companies, said he could not elaborate on the raid or the investigation.

"I had no knowledge of anything, and we have done nothing wrong," Halac said. "I don't know any reason why this happened."

Halac, who lives in Ashburn Village, said he founded the companies more than eight years ago to manufacture structural steel. He would not disclose the number of people he employs or any other details, referring inquiries to Reed.

"I have no knowledge of any of the numbers," Halac said, adding that Reed is "getting the details."

The Halac companies are housed in corrugated steel warehouse-style buildings in an industrial area on a wooded road off Route 28 near Dulles International Airport. Employees leaving the gated property Thursday declined to comment on their work or the INS arrests.

The 17 undocumented workers who were arrested Nov. 3 were taken to the INS field office in Alexandria, according to the INS statement.

Thirteen of the employees could be deported for violating immigration laws, said INS spokeswoman Ernestine Fobbs. Three others were released after the INS determined that they have active applications seeking benefits under the U.S. Immigration and Nationality Act.

The other employee was detained for failure to have immigration documents in his possession. The employee, who is a native of Cyprus, was released after agents determined that he had proper documentation, Fobbs said.

The employees who are facing possible deportation come from El Salvador, Mexico, Honduras, Guatemala and Hungary. Fobbs said they are being "processed to see whether a bond will be issued on their behalf."

After that, she said, deportation could occur quickly. "They may very well be subject to immediate removal from the U.S.," Fobbs said.

Staff writer Maria Glod contributed to this report.