From negotiating with Hezbollah to tracing stolen toxic waste, Werner Mauss was one of Germany’s most prolific secret agents

In secret service circles, he was either known as “Institution M” or “The Man with Nine Fingers”, because of a missing digit on his left hand. Locals in his village thought he was called “Richard Nelson” but his bank clerk knew him as “Claus Möllner”. Politicians at the top of government simply referred to their top secret agent as “007”.

For at least three decades Werner Mauss was Germany’s real-life answer to James Bond: a rogue operator who moved in the shadowy realm between criminal underworld and intelligence agencies, entrapping drug dealers, retrieving stolen goods, negotiating with terrorists, often changing identity on his private plane mid-air.

But now, at the end of a career of dodging bullets and speeding cars, the 77-year-old has been caught in the web of a more mundane nemesis: the taxman.

On Monday, Mauss will appear in a county court in Bochum for the closing argument of a trial in which he stands accused of evading €14m (£12.3m) in tax to help fund a lifestyle of fast cars and thoroughbred horses. If the state prosecution has its way, he could be sentenced to six years and three months in prison by the end of the week.

Facebook Twitter Pinterest A sketch of Werner Mauss, printed in Der Spiegel in November 1985. Photograph: Der Spiegel

Born in 1940 in Essen, Mauss had discovered his talent for winning over the trust of strangers while working as a door-to-door vacuum cleaner sales rep. While still in his 20s, he started a detective agency which he ran with his first wife, spying first on cheating husbands and insurance scammers, then moving on to criminal gangs.

Mauss would pretend to be a dealer interested in buying stolen cars, furs or jewellery, and tip off the police once the thieves had confided in him the details of their next robbery. His method, he told journalist Stephan Lamby for a 1998 documentary, consisted of “leading the target through different psychological rooms” and then confronting them with intellectual challenges that forced them to reveal more than they intended.

From 1970 to 1996, Mauss’s name was mentioned in connection with almost every major criminal case in West Germany: according to a biography by journalist Stefan Aust, he claimed to have orchestrated the arrest of no fewer than 162 diamond smugglers, burglars and drug dealers between June 1970 and May 1971 alone.

In 1976, Mauss personally arrested a member of leftwing terror group the Baader-Meinhof gang at a newsagent in Athens. In 1983, the government commissioned him directly to retrieve 41 barrels of toxic waste that had gone missing during transport, which the undercover detective promptly discovered on a farm in northern France.

In the late 1980s and 1990s, the self-made secret agent went global, negotiating with Hezbollah to free industrialists kidnapped in Lebanon, and trekking through the South American jungle to achieve the release of a German citizen held by ELN guerrillas.

The latter mission eventually led to Mauss’s unmasking by the Colombian government, which was concerned that he was collaborating with kidnappers to drive up the ransom money. After being sent to prison for nine months, he was cleared of charges in 1998.

With the double 0 lifestyle also came a suitably expensive taste: Swiss watches, fur coats, luxury hotels, Porsches, Jaguars and a Cessna 172, in which Mauss was able to fly directly to missions around the world from a runway on his 40,000 acre estate in the Hunsrück region in Germany’s southwest.

Facebook Twitter Pinterest Werner Mauss and his private plane Photograph: Süddeutsche Zeitung

The fenced-off property, which Mauss acquired at the end of the 1960s, has over years grown into what local newspaper Rhein-Zeitung calls a “Disney World castle”, complete with pagodas, a landscaped private zoo with mouflon, ibex, chamois, cranes and peacocks, and the biggest private riding hall in Germany.

Germany’s state prosecutor believes Mauss has funded these expensive habits via two UBS offshore accounts in Luxembourg and the Bahamas, all while failing to pay tax on capital assets worth more than $50m (£36.8m) between 2002 and 2012 alone. One UBS manager interviewed by investigators said that Mauss had regularly travelled to Luxembourg to withdraw cash from his account, “around €300,000 per month”.

Germany’s tax office had got wind of Mauss’s offshore activity after purchasing leaked Swiss bank data in 2012. Last year, daily Süddeutsche Zeitung discovered one of the special agent’s aliases in the Panama Papers leak and made the investigation public.

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Mauss claims that he did not have to pay tax on the money in the UBS accounts because it had come from a trust fund set up by western intelligence agencies to support his “covert fight against crime and terrorism”.

In the year-long trial at Bochum county court, Mauss appeared on court days wearing a hooded jacket to shield himself from photographers, even though his website werner-mauss.de features a video clip in which he is clearly identifiable.

The 77-year-old has insisted that he continues his Bond-like activity to this day, in spite of his unmasking in 1996. Mauss not only cited operations in Iraq, Israel, Myanmar and Thailand but also claimed to be currently engaged in the “fight against Isis”. As recently as 2011, he told his investigators, the trust fund had enabled him to save Pope Benedict XVI from attempted poisoning by the Sicilian-Colombian drug mafia, thanks to a tip-off from the Chinese secret service.

Star witnesses who Mauss had promised would confirm his version of events never materialised, however. One, a deputy of the Federal Police Agency, turned out to have died over five years ago. Neither could the secret agent explain to the prosecutor why foreign intelligence agencies would have set up a trust fund whose statutes stipulated that monies would be channelled towards the creation of a “Werner Mauss museum” after his death. His defence, said state prosecutor Timo Dörfer, had “trickled away like sand between his fingers”.

On Monday, Mauss’s team defence lawyer will get a final hearing, after which the judge Markus van den Hövel has 11 days to pass a sentence. .