Intel under scrutiny

Scandals have become almost synonymous with the German intelligence service, the Bundesnachrichtendienst (BND), in recent years, and the information that floods the public sphere comes so thick and fast that much gets lost in the mix.

To put the latest allegations into context - that is, the claims that the BND spied on European companies and politicians at the behest of America's National Security Agency (NSA) - requires a journey back in time: to almost a decade before whistleblower Edward Snowden first made the headlines.

In 2002, with the September 11, 2001, terrorist attacks fresh in international memory, a German-US intelligence cooperation deal was sealed in a Memorandum of Agreement.

Authorized by then-chief of the German Chancellery and current foreign minister, Frank-Walter Steinmeier, the document cleared the way for Germans or Americans in Germany to be spied on. Equally, it was devised to prevent the economic interests of German and European companies from being compromised.

Under its terms, the NSA regularly passed so-called selectors - IP adresses and phone numbers - onto BND staff, who fed them into their system, the idea being to work together to counter terrorism.

US accused of seeking to broaden its reach

In 2006, however, BND staff members at the monitoring station in Bad Aibling - which was built by the United States in the 50s and handed over to Germany in 2004 - are reported to have told BND headquarters that NSA selectors had begun to appear in connection with the European Aeronautic Defense and Space Company (EADS), now known as the Airbus Group.

Two years later, in 2008, the mass-circulation "Bild am Sonntag" newspaper leaked a report claiming that the NSA was trying to use Bad Aibling to harvest information about EADS and its Eurocopter subsidiary. Current Interior Minister Thomas de Maiziere was chief of the Chancellery at the time and, as such, responsible for the BND and Germany's other intelligence agencies.

In 2010, a report in Germany's "Der Spiegel" new magazine claimed the Chancellery had been informed that EADS, Eurocopter and French members of parliament were among the NSA's surveillance targets. Chief of the Chancellery at the time, Ronald Pofalla, is alleged to have told the BND to filter the NSA search requests more stringently to ensure that German citizens and companies and European partners were not spied on.

In June 2013, Edward Snowden shocked the world with information he provided to reporters revealing that the NSA, for whom he had previously worked, operated a policy of sweeping and systematic surveillance of Internet and telephone activity. Later that summer, in August 2013, the BND ran checks of the US selectors used at Bad Aibling.

According to "Der Spiegel," that investigation revealed various search terms used in connection with email addresses of numerous French diplomats and European politicians. BND President Gerhard Schindler was allegedly not informed.

Merkel revealed as a tapping target

Also in August 2013 it emerged that Chancellor Angela Merkel's telephone had been tapped by US intelligence services - just days after then Chief of the Chancellery Ronald Pofalla said NSA had pledged not to violate German law in its intelligence activities.

In March 2014, the German parliament established an investigative committee to reveal the full extent of NSA activities on its turf. In August the same year, it emerged that the BND had spied on Turkey and "accidentally" intercepted Hillary Clinton's and John Kerry's phone calls.

In March 2015 the BND's Gerhard Schindler told the Chancellery that his staff had long been aware of irregular search terms at Bad Aibling, but had only just reported them to him. He also claims not to have known about a list of some 40,000 NSA selectors his staff had been weeding out of those put forward for searches since 2002.

In mid-April 2015, in response to a parliamentary request from the Left Party, Interior Minister Thomas de Maiziere said there were "still no findings to suggest industrial espionage at the hands of the NSA ,or other US services in other states."

A week later, "Der Spiegel" reported that the BND had been aware that some NSA selectors since 2008 indeed related to European defense companies and French politicians during de Maiziere's time as chief of the Chancellery.

The unknown of the coming days and weeks

The interior minister has denied any wrong doing, saying he welcomed the opportunity to testify at a hearing in front of an investigative committee. Current chief of the Chancellery, Peter Altmaier, will also face official questioning.

Opposition politicians are calling for definitive light to be shed on the inner workings of the country's intelligence service, and several have called for both de Maiziere and Schindler to resign. Left Party leader Gregor Gysi has demanded that Merkel testify under oath about her knowledge of BND activities.

On Monday, the chancellor said the BND had to continue cooperating with international partners, and that to "carry out its responsibilities combating international terrorist threats requires collaboration with other agencies, starting with the NSA."

A preliminary inquiry has been launched by Germany's federal prosecutor, Harald Rang, who will be questioned himself by a parliamentary committee looking into the affair.