The investigation into the so-called diplomatic treason related to the Smolensk disaster lasted a full 10 years. The National Prosecutor's Office analyzed the actions of Polish authorities in April and May 2010, immediately after the tragedy in which 96 people died on Russian territory, including President Lech Kaczyński and his wife. During this 10-year investigation, a total of 488 witnesses were interrogated. As emphasized by the spokesperson for the National Prosecutor's Office, Przemysław Novak, during a press conference on Wednesday, investigators found no signs of a crime. "The investigation, which lasted 10 years, showed that the actions of Polish authorities in April and May 2010 contained no signs of a crime in the form of diplomatic treason," said Novak. Novak also noted that the main investigation into the disaster, initiated in 2010, is still ongoing at the General Prosecutor's Office. He reminded that in recent days, a translation of an additional report from the International Expert Group was received by Investigation Group No. 1 of the National Prosecutor's Office. As he pointed out, this comprehensive report "was supposed to answer the question, in very general terms, what caused the Smolensk disaster." As is known, on April 10, 2010, a Tu-154M aircraft crashed at the "Severny" airport near Smolensk, resulting in the deaths of 96 people, including President Lech Kaczyński and his wife Maria, senior military commanders, and the last president of the Republic of Poland in exile, Ryszard Kaczorowski.