Bayern Munich president Uli Hoeness was arrested on March 20 and later set free on a €5 million bail, German daily Sueddeutsche Zeitung reported on Tuesday.
Hoeness is currently under investigation for tax evasion after filing a voluntary disclosure in January over a sum of money held in a Swiss bank account, which was reported to have been used to gamble on the stock exchange. The 61-year-old could face court proceedings.
Sueddeutsche Zeitung highlights the fact that, under German law, a voluntary disclosure – if filed correctly and at the appropriate time – leads to exemption from penalty. However, his temporary arrest last month, the paper said, represents "a serious hint" that his actions "might not be able to go unpunished".
The 61-year-old, who attended his club's 4-0 victory over Barcelona on Tuesday at the Allianz Arena, had told Focus that his intention had been to come forward using a German-Swiss agreement that would allow those evading tax to pay the arrears anonymously.
However, the measure was defeated by the opposition to Chancellor Angela Merkel's government on the grounds that it represented an amnesty to those guilty of evading tax.
In an interview with Sport Bild on Wednesday, Hoeness admitted he had made a "substantial mistake" but was not trying to "partially make up for it with the voluntary disclosure".
The Hoeness case has gained nationwide attention and become one of the major topics in the build-up towards the national election in September, with taxes and tax evasion being one of the main political issues in Germany. Merkel is said to be "disappointed" by the Bayern president's actions.