SAN DIEGO -- Federal investigators Tuesday searched the North County offices of a firm with ties to embattled U.S. Rep. Randy "Duke" Cunningham, R-Escondido, according to the FBI.

Agents with the bureau, the Internal Revenue Service and Defense Criminal Investigative Services served a warrant at the headquarters of ADCS Inc. on Stowe Drive in Poway, FBI Special Agent Kiffa Shirley said.

Shirley said he could not disclose the reason for the morning raid, nor any other details of the probe.

Officials with ADCS, which specializes in converting paper documents into computer records, and the firm's political action committee reportedly have contributed at least $30,000 to Cunningham's campaign coffers since 1996.

In other developments in controversies surrounding the eight-term congressman, a federal grand jury has subpoenaed a defense contractor affiliated with an investigation of Cunningham.

The owner and former president of MZM Inc., Mitchell Wade, reportedly has been ordered to appear before the panel at an undisclosed time. It was unclear when the subpoena was sent.

Wade is at the center of the federal grand jury investigation examining whether Cunningham, a member of the House Appropriations Committee, improperly influenced the awarding of Pentagon defense contacts to MZM.

Wade's 2003 purchase of Cunningham's Del Mar Heights home at an apparently inflated price triggered the probe.

ADCS Inc. also has received millions of dollars worth of military contracts over the last nine years and has ties to Wade, according to published accounts.