Parliament speaker and acting head of state, Bronislaw Komorowski (L), speaker of the Senat, Bogdan Borusewicz (C) and Prime minister Donald Tusk (R) pay their respects in memory of the victims of the air-crash in which President Lech Kaczynski was killed in front of Parliment in Warsaw on April 11, 2010. Russian investigators said they were working closely with their Polish counterparts to determine the cause of the plane crash that killed Poland's president Lech Kaczynski. AFP PHOTO /JANEK SKARZYNSKI