That means mole.

German politicians hail capture of suspected Russian ‘mole’ – The capture of an alleged Russian spy in Germany’s intelligence agencies has been called a “wake-up call” by politicians who are concerned by the threat of hybrid warfare.

“The fact that there are Russian espionage activities in Germany is well known and hardly surprising. But if now even in the ranks of the BND an employee is said to have spied for Russia, then this would be a completely new and frightening quality. Of course, this also raises the question of the effectiveness of the BND’s own security.”