President of the European Council Donald Tusk speaks to the media outside the prosecutor's office in Warsaw, Poland, Thursday, Aug. 3, 2017.  Polish investigators questioned Donald Tusk as a witness Thursday in an investigation into the 2010 plane crash that killed President Lech Kaczynski - a case widely seen as a politically-driven attempt to discredit the EU leader. (AP Photo/Czarek Sokolowski)