Germany has arrested former foreign intelligence chief August Hanning on suspicion of treason and espionage. Federal prosecutors announced the arrest on Tuesday.

Hanning, 80, led the Federal Intelligence Service, known as the BND, from 1998 to 2005. He was detained in Bad Toelz-Wolfratshausen in southern Germany. A former aide identified as Manfred D. was also arrested in Steinfurt.

Prosecutors say Hanning is strongly suspected of treasonous espionage, spying out state secrets and attempted treason. They allege the aide supplied him with about 2,000 classified documents over several years in exchange for payment.

According to investigators, the arrangement began around 2010. Hanning allegedly used the material in his private consulting work and prepared at least one security analysis for an officer of a foreign intelligence service. Prosecutors have not named the foreign power involved.

Treason carries a maximum penalty of life in prison in Germany. The case is an embarrassment for Berlin, which recently approved a major overhaul giving intelligence agencies broader powers. Both men’s properties were searched on Tuesday.