The Prosecutor’s Office of Poland may launch an investigation into whether the country’s current president and prime minister acted against Poland’s interests during the investigation of the plane crash in which former president Lech Kaczynski died.

According to the claim by Berlin lawyer Stefan Hambura, President Bronislaw Komorowski and Prime Minister Donald Tusk committed an offence against Poland when they refused the Russian offer of a joint investigation into the crash of Kaczynski’s plane. Hambura, who represents the son of Anna Walentynowicz, a political activist also killed in the crash, reported the offence to the Prosecutor’s Office of Poland in July, Polish Wprost newspaper writes. Hambura cited the suggestion of Russian President Dmitry Medvedev to investigate into the crash together and noted that the actual probe only lasted three days.