German prosecutors allege that Hanning, who has worked as a private consultant since leaving the BND, used classified intelligence to draft an analysis for an officer of one foreign intelligence service and maintained close contact with a representative of another foreign spying service. Investigators have not disclosed which foreign powers were involved.
Alongside Hanning, police arrested Manfred D, a former BND employee who served as Hanning's bureau chief and remained with the agency until this year. Manfred D is charged with aiding and abetting attempted treason and treasonous espionage. Prosecutors say he used his role to access highly confidential information, which he passed to Hanning for remuneration over a period of years.
"The current findings suggest that, over the years, Manfred D provided Hanning with approximately 2,000 documents, many of which contained classified information to be used exclusively by the Federal Intelligence Service for internal purposes," prosecutors said in a statement.
On one occasion, Hanning used classified intelligence to draft an analysis for an officer of a foreign intelligence service, though it is unclear whether the material reached its intended recipient.
Local media reported that Hanning was arrested at his home in Nordwalde near Münster, while Manfred D was arrested in Bavaria. Hanning is due to appear in court on Wednesday and Manfred D on Tuesday.