Polish parliament in the context of 2010 Polish Air Force Tu-154 crash

The Institute of National Remembrance – Commission for the Prosecution of Crimes against the Polish Nation (Polish: Instytut Pamięci Narodowej – Komisja Ścigania Zbrodni przeciwko Narodowi Polskiemu, abbreviated IPN) is a Polish state research institute in charge of education and archives which also includes two public prosecution service components exercising investigative, prosecution and lustration powers. The IPN was established by the Polish parliament by the Act on the Institute of National Remembrance of 18 December 1998 through reforming and expanding the earlier Main Commission for the Investigation of Crimes against the Polish Nation of 1991, which itself had replaced the General Commission for Research on Fascist Crimes, a body established in 1945 focused on investigating the crimes of the Nazi administration in Poland during World War II.

In 2018, IPN's mission statement was amended by the controversial Amendment to the Act on the Institute of National Remembrance to include "protecting the reputation of the Republic of Poland and the Polish Nation". The IPN investigates and prosecutes Nazi and Communist crimes committed between 1917 and 1990, documents its findings, and disseminates them to the public. Some scholars have criticized the IPN for politicization, especially under Law and Justice governments.

On 10 April 2010, a Tupolev Tu-154 aircraft operating Polish Air Force Flight PLF 101 crashed near the Russian city of Smolensk, killing all 96 people on board. Among the victims were the president of Poland, Lech Kaczyński, and his wife, Maria; the former president of Poland-in-exile, Ryszard Kaczorowski; the chief of the Polish General Staff and other senior Polish military officers; the president of the National Bank of Poland; Polish government officials; 18 members of the Polish parliament; senior members of the Polish clergy; and relatives of victims of the Katyn massacre. The group was arriving from Warsaw to attend an event commemorating the 70th anniversary of the massacre, which took place not far from Smolensk.

The pilots were attempting to land at Smolensk North Airport — a former military airbase — in fog, with visibility reduced to about 400 metres (about 400 yards). The aircraft descended far below the normal approach path until it struck trees, rolled, inverted and crashed into the ground, coming to rest in a wooded area a short distance from the runway.