Germany’s former foreign intelligence chief August Hanning has been arrested on suspicion of treason in what prosecutors believe could be the biggest national security breach since the cold war.
Hanning is accused of having spent the last 16 years illegally acquiring thousands of classified documents from the very top of German intelligence, and selling at least some of the information gleaned from them to a foreign power.
Officials familiar with the investigation said that Russia was not currently part of their investigation.
Hanning was taken into custody by German police at his home in Steinfurt county, near the Dutch border, on Tuesday morning, under orders from the German federal prosecutor.
The 80-year-old served as head of the Bundesnachrichtendienst (BND) from 1998 to 2005. From 2005 to 2009 he was the most senior civil servant in Germany’s interior ministry.
He did not immediately respond to a request for comment.
A serving senior BND official named by police as “Manfred D” was also taken into custody from his home in Bavaria on suspicion of aiding in treason.
Manfred D served as Hanning’s chief of staff during his tenure as BND head and followed him to work at the interior ministry.
After Hanning’s retirement, he went back to work as chief of staff for three successive BND chiefs from 2012 onwards until he left the agency this year — a position and length of experience that gave him access to sensitive decision-making and classified materials at the very top of the agency.
“Both suspects are believed to have agreed, in the spring of 2010, to have Manfred D continuously transmit valuable intelligence from the Federal Intelligence Service to Hanning in exchange for remuneration,” the federal prosecutor said in a statement.
“Hanning was to capitalise on said information in the context of his private consulting services, which he had since been offering. 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 BND for internal purposes, particularly for executive intelligence briefings.”
Executive intelligence briefings are the classified dossiers prepared by the BND for the German chancellor and a small group of other security-cleared ministers.
The grade of intelligence materials involved in the leak will raise urgent questions among the BND’s close partners worldwide. As Europe’s biggest intelligence service, the BND is a routine recipient of highly classified information from agencies such as the CIA, MI6 and DGSE. The sharing of such information is dependent on total confidence that it will not be leaked or shared with third parties.
According to German prosecutors, on at least one occasion, Hanning used information from classified BND documents to draft a briefing for “an officer of a foreign intelligence service”. It was unclear whether the briefing, which had been found in Hanning’s possession, was ever actually sent to that service, they said.
Hanning passed on “political” information informally to an official he was on good terms with at a second foreign intelligence service “for years”, the prosecutor added.
Hanning is the highest-profile individual accused of treason in Germany since the Guillaume affair of 1974, when Günter Guillaume, one of chancellor Willy Brandt’s closest advisers, was exposed as a long-term Stasi agent. Brandt subsequently resigned.
News of Hanning’s arrest comes as the government of Chancellor Friedrich Merz is trying to pass landmark reforms for Germany’s intelligence agencies, intended to give them sweeping new powers.
The BND has only just begun to move on from its last security breach: Carsten L, the head of a department within the agency, was arrested in 2022 on allegations of having spied for Russia.
He leaked highly sensitive documents to the Kremlin from the heart of the BND in what the agency’s then head, Bruno Kahl, described as a “catastrophe”.
Carsten L denies the allegations. His trial is ongoing.
Investigators began looking into Hanning’s affairs as a result of an unrelated probe.
A regional prosecutor in Hamburg ordered a search of Hanning’s home in September 2025 in connection with a high-profile child custody case involving the multi-millionaire heiress of a German steakhouse restaurateur, in which Hanning had provided consultancy services.
After discovering classified BND material, Hamburg investigators passed on their evidence to the federal prosecutor, who opened their own investigation against Hanning in May.