German police have arrested Markus Braun, the former chief executive of the Munich-based fintech company Wirecard, for fraud, prosecutors in Munich said on Tuesday. Braun turned himself into German authorities on the same day Wirecard admitted that $2.1 billion the company had reported on its balance sheet did not exist. He has since been released on €5 million bail. That revelation came three days after Braun resigned as the chief executive of the company he led for more than a decade, and four days after Wirecard announced that auditors from…