Wirecard became the first-ever DAX member to file for insolvency in 2020, owing creditors almost $4 billion, after disclosing a 1.9 billion euro ($2.13 billion) hole in its accounts.

The firm's auditor, EY, said the hole was the result of sophisticated global fraud in a case that sent shockwaves through the country's political and financial establishment. The trial of former Wirecard executives kicked off last December.

Marsalek, Wirecard's former chief operating officer, is considered a key figure in the Wirecard scandal and an international fugitive on Europe's most-wanted list.

In July he had contacted the Munich court through his lawyer - although neither the lawyer nor authorities disclosed the content of this written communication. A court spokesperson said on Friday that lawyer would now be questioned as a witness in the case.

(Reporting by Joern Poltz; Writing by Sarah Marsh; Editing by Leslie Adler)