A former executive at the German financial services company Wirecard, Jan Marsalek, sought by Interpol following the firm's stunning collapse in 2020, could be hiding in Moscow, according to a report Monday.

Marsalek moved into a "gated community" in the Russian capital after the scandal under the "care" of the FSB, the Russian secret service, and could still be there today, the German daily Bild reported.

In Moscow, Marsalek was involved in trading the Russian "Sputnik V" vaccine against the coronavirus and was in contact with "paramilitary mercenaries", according to the tabloid.

The FSB offered their German counterparts the opportunity to "interrogate" Marsalek in 2021, Bild said. Local officials in Moscow contacted central German intelligence in Berlin to ask "if a meeting with Marsalek should take place".

But the question from the Moscow office went "unanswered" by colleagues in the capital, according to Bild, though the German government was "informed".

Once the standardbearer for the German tech industry, Wirecard collapsed in June 2020 after admitting that a missing 1.9 billion euros ($2 billion) from its balance sheets likely didn't exist.

The scandal was "unparallelled" in Germany's history, according to the then finance minister Olaf Scholz, who is now chancellor.

The company's CEO, Markus Braun, was charged with fraud by German authorities earlier this year.

Marsalek, an Austrian national considered to be Braun's right-hand man, has been on the run since the collapse.