Former State Department official Walter Kendall Myers and his wife were arrested and indicted Friday for allegedly spying for Cuba since the 1970s.

Myers, a former official in the State Department's Bureau of Intelligence and Research who retired in 2007, is said to have worked as an agent of the Cuban Intelligence Service along with his wife, Gwendolyn.

Charges of conspiracy, being an agent of a foreign government, wire fraud, forfeiture, and aiding and abetting were filed against Walter and Gwendolyn Myers in the federal district court for Washington, D.C. on Friday.

"The clandestine activity alleged in the charging documents, which spanned nearly three decades, is incredibly serious and should serve as a warning to any others in the U.S. government who would betray America's trust by serving as illegal agents of a foreign government," Assistant Attorney General for National Security David Kris said in a statement announcing the indictments.

As a State Department Employee, Myers has had access to some classified information since 1978.

The indictment said that the alleged "conspiracy" persisted from 1979 to "on or about June 4, 2009."

The indictment accuses the couple of working to undermine the day-to-day function of the State Department.

It is not clear whether Gwendolyn Myers had once served as a congressional aide, as had previously been reported.

The detailed indictment unveiled today even goes so far as to say the couple had used shortwave radio and morse code to communicate messages to the Cuban government.

According to the indictment, the FBI had run an undercover sting at a Washington, D.C. hotel against Walter Myers in mid-April of this year.

"These arrests are the culmination of an outstanding counterespionage effort by many agents, analysts and prosecutors who deserve special thanks for their extraordinary work," Kris said.