A series of recorded telephone calls among bank employees revealed that the bank received a tip off from within the German authorities, though it is not clear from which office the leak came.
According to a report in Saturday's edition of the Süddeutsche Zeitung newspaper, the employees, all of whom face major tax evasion charges, were recorded talking about a raid that took place on April 28, a day before it happened.
State prosecutors carried out a raid on 230 companies, banks and apartments throughout Germany on that day, including some Deutsche Bank offices. The operation was related to an investigation into an international fraud ring that is said to have evaded sales tax on emissions rights trades, which the bank was involved in.
The justice ministry of the state of Hesse confirmed that it had opened an investigation into a possible "breach of official secrets protocol." Deutsche Bank refused to comment on the allegations.