Deutsche Bank said Wednesday that one of its co-chief executives Juergen Fitschen is under investigation in an ongoing probe into alleged tax fraud at Germany's biggest lender.

Prosecutors and tax police raided the offices of Deutsche Bank Wednesday in a probe dating back to 2010, and "in connection with this, two management board members Juergen Fitschen and Stefan Krause are also being investigated," Deutsche Bank said in a statement.

Deutsche Bank said Wednesday that one of its co-chief executives, Juergen Fitschen, is under investigation in a probe into tax fraud at Germany's biggest lender.

The allegations date back to the spring of 2010 and concern "individuals suspected of tax fraud in connection with trading in carbon emissions certificates," the statement said.

Fitschen and Krause, who is the bank's finance chief, are under investigation because they signed off the bank's 2009 valued-added tax (VAT) declaration, the bank explained.

"But that tax declaration has since been corrected voluntarily by the bank. Unlike the prosecutors, Deutsche Bank is of the opinion that the corrected declaration was submitted in a timely manner," it said.

"Deutsche Bank is cooperating fully with the authorities," it added.