Deutsche Bank co-CEO Jürgen Fitschen, already the subject of a German tax-fraud probe, has come under further pressure after political leaders accused him of trying to influence the investigation by calling a senior German politician to protest a police raid on the bank's headquarters last week.

On Thursday, a day after the surprise search, Fitschen contacted Volker Bouffier, governor of the state of Hesse, where Deutsche Bank is based, to complain about the action. Bouffier declined to intervene, according to his spokesman. The state government has ultimate authority over the prosecutor's office.