JACKSONVILLE, Fla. -- Channel 4 on Friday learned new information about the FBI's investigation into business dealings involving the Jacksonville Port Authority and one of the port's board members.

Last week, FBI agents raided several local companies, including one belonging to well-known Jacksonville businessman and Jaxport board member Tony Nelson. Days later, Nelson took a voluntary leave of absence from his board position with the Jaxport.

The FBI did not disclose the nature of their investigation or what they were looking for at Nelson's offices, but they seized documents that have to do with contracts with the port.

Subaqueous Services Inc., a dredging company, and Rham Construction are the two companies not affiliated with Nelson that were raided by the FBI. Both have done business with the port.

While the FBI and the U.S. attorneys office would not comment about the investigation concerning the port or Nelson and several employees and companies doing business with the port, a copy of the subpoena the FBI served port officials reveals that investigators are looking at two other businesses involved in work at the new port site.

The subpoena calls for port officials to turn over disciplinary actions, travel records, appointment calendars and other records for the port's chief financial officer Ron Barker, its Government Affairs Director Eric Green and the man who is overseeing the new multi-million dollar port expansion near Blount Island, David Smolder.

Channel 4's reporter Jim Piggott tried to reach Nelson, Barker, Green and Smolder, but only the port's public relations director would speak out about the investigation.

"We are cooperating fully with all of the inquires and request for information, and our executive director has directed the staff and all employees to do the same," said Jacksonville Port Authority spokeswoman Nancy Rubin.

While it's known investigators are looking at two other businesses involved in work at the new port site, it remains unclear exactly what they suspect or who is involved.