August Hanning knows the world of espionage well. For seven years, he headed Germany’s Federal Intelligence Service, the BND, and in that capacity was exposed to some of the country’s most sensitive secrets.

On Tuesday morning, more than two decades after leaving the post, he was himself arrested on suspicion of espionage.

The affair rocking Germany involves thousands of classified documents, suspected payments, contacts with foreign intelligence officials and a surprising connection to Israel: The investigation that led to its exposure actually began with the case involving the abduction of millionaire heiress Christina Block’s children, in which Israelis were also implicated.

Hanning, 80, was arrested at his home in Nordwalde in western Germany. At the same time, Manfred D., who formerly served as his chief of staff and later continued in a senior position at the BND, was arrested in Bavaria.

According to Germany’s federal prosecutors, Hanning is suspected, among other things, of espionage amounting to treason, obtaining state secrets and acting on behalf of a foreign intelligence service. At this stage, authorities have not disclosed which intelligence service is involved.

A joint investigation by WDR, NDR and the Süddeutsche Zeitung provides a glimpse into how the alleged operation was conducted over the course of several years.

According to the allegations, as early as the spring of 2010, about five years after Hanning stepped down as head of the BND, he reached an arrangement with his former aide: Manfred D. would continue supplying him with information from inside the intelligence service in exchange for money.

D. had extraordinary access to classified material. After serving as Hanning’s chief of staff, he remained with the agency, and between 2012 and March 2026 held a position that gave him access to sensitive information during the tenures of subsequent BND chiefs as well.

As a result, investigators suspect that Hanning obtained approximately 2,000 documents over the years.

The material allegedly went far beyond internal paperwork. According to the German investigation, it included documents prepared for intelligence meetings at the Chancellor’s Office, as well as reports on particularly sensitive subjects, including Iran’s nuclear program and the Russian military.

Some of the material - perhaps one of the most troubling aspects of the affair for Berlin - also included intelligence provided to Germany by the intelligence services of partner countries. For an intelligence agency, such a leak is not merely an internal problem: It could cause foreign partners to think twice before sharing sensitive intelligence with Germany.

According to prosecutors, Hanning used the information in his business activities as a consultant following his retirement. Investigators are also examining suspicions that, in one case, the material was used to prepare a security analysis for an official from a foreign intelligence service.

The identity of that service has not been disclosed. German media have also focused on Hanning’s contacts over the years with figures in Russia and China. However, the investigation by WDR, NDR and the Süddeutsche Zeitung stressed that the case in which the analysis was allegedly prepared for a foreign intelligence official was not connected to Russia.

There is another detail that makes the story unusual: Investigators stumbled upon the alleged espionage almost by accident.

Hanning had already come under scrutiny by authorities as part of an entirely separate case - the case of Christina Block, heiress to a German restaurant empire, who is standing trial over the abduction of two of her children from Denmark to Germany amid a bitter custody dispute with her former husband.

That case also attracted attention in Israel. The investigation implicated Israelis, including security personnel, and reports about the affair also mentioned former members of Israel’s security establishment.

Hanning’s name was linked to allegations concerning an earlier attempt to return the children to Germany, claims that he denied. As part of that investigation, investigators searched his home and office in September of last year and seized equipment for examination.

That, according to the German investigation, is where the case took a dramatic turn. Secret BND documents were discovered on an electronic storage device seized from Hanning. The problem was obvious: Hanning had left the intelligence service in November 2005 and therefore should not have had access to current intelligence material.

Investigators began pulling at the thread, and the scope of their suspicions expanded. According to German sources, the most recent documents discovered dated from 2022. By May of this year, federal prosecutors had opened a covert investigation into Hanning and the individual suspected of being his source inside the intelligence service.

It is important to emphasize that the Israeli connection does not mean that the foreign intelligence service for which Hanning allegedly acted was Israeli. The German sources do not suggest that. The Israeli connection lies in the chain of events that led to the affair being uncovered: The investigation into the Block case, in which Israelis were implicated, led to the search of Hanning’s property; the search led to the documents; and the documents triggered an espionage investigation at the heart of Germany’s intelligence establishment.

Hanning now finds himself in a very different position from the one he occupied for years. The man who was once responsible for gathering intelligence on behalf of Germany must now confront allegations that he himself used the agency’s secret information after leaving office - and that some of that information was even used in connection with a foreign intelligence official.