Prosecutors have raided  Deutsche Bank’s headquarters in Frankfurt this week after suspicions of tax fraud relating to client securities transactions surfaced. The Financial Times reports that about 30 plain-clothes officers were part of the search, which began on Tuesday morning.

The alleged transactions involved “dividend stripping,” a strategy used to reduce  tax burdens, where an investor obtains tax free dividends by investing in securities during a specific time to incur a short-term capital loss. In recent years, Germany has made significant moves to crackdown on tax evasion schemes by working with U.S.  and Swiss authorities—while this loophole is now closed, significant legal issues still exist.  

The German bank, has been caught in a swirl of regulatory problems. Earlier this week, Deutsche’s Chief Executives Anshu Jain and and Jurgen Fitschen announced their plans to step down from the helm. Both co-chiefs were under increasing scrutiny after failed attempts to help the firm regain its financial stability and meet new regulatory requirements. Last month,  Deutsche Bank agreed to pay a $55 million penalty to the Securities and Exchange Commission to resolve charges that it filed misstated financial reports during the height of the financial crisis that failed to take into account a material risk for potential losses estimated to be in the billions of dollars.

Deutsche bank has most recently been at the center of many scandals. In Europe, regulators are looking into the bank’s role in high frequency trading and anti-money laundering practices. A spokesman for the German prosecutor’s office told Reuters that they have carried out "wide-ranging investigative measures," but declined to provide specifics.