The assassination of Bronisław Pieracki was a target killing of a Polish politician of the interwar period, Minister of Interior Bronisław Pieracki (1895-1934), by the Organization of Ukrainian Nationalists (OUN).

The chosen assassin, Hryhorij Maciejko pseudonym "Gonta", was a trusted member of OUN.^[2]

The OUN was formed in Poland in 1929 by a number of nationalist organizations. It professed ethno-nationalism, including hostility to Poles, and in its first decade carried out many acts of terrorism, including political assassinations.^[3][4]

The assassination plan was decided at an OUN meeting in Berlin. Maciejko was supplied with a makeshift bomb and a 7.65mm caliber pistol from Bandera.^[1] In the morning of 15 June 1934 Maciejko (aged 31) appeared at the Foksal Street in Warsaw in front of a social club frequented by Pieracki. He waited there for several hours undetected. The minister arrived in his limousine at 3:30 pm; however, Maciejko's bomb failed. He pulled the gun and shot the minister from behind twice in the back of his head.^[2] Maciejko escaped successfully with the help of OUN emissaries as far as Czechoslovakia and then on to Argentina.^[5]

Pieracki's state funeral was attended by some 100,000 people. The coffin was sent to Nowy Sącz in a special train and laid in his family tomb.^[6]

Despite the assassin dropping a blue and yellow ribbon, a symbol of the OUN terrorist organisation, at the scene of the crime,^[7] the Polish authorities professed not to realize that OUN was behind the assassination and blamed the Polish National Radical Camp (ONR) for it. The mistake had terrible consequences for Poland's political life.^[5] As a result of this, the Bereza Kartuska prison for dissidents was established.^[2]

A year later, it became known that OUN was behind the assassination of Bronisław Pieracki. The trial of OUN leaders before a Warsaw circuit court took place between 18 November 1935 and 13 January 1936. Sixteen OUN members, including Stepan Bandera and Mykola Lebed, were found guilty of organizing the assassination.^[6]

After a two-month trial in Warsaw, the court sentenced the guilty as follows:

• Stepan Bandera, Mykola Lebed and Yaroslav Karpynets were sentenced to death (commuted to life imprisonment due to an amnesty);
• Mykola Klymyshyn, Bohdan Pidhainy sentenced to life imprisonment;
• Dariya Hnatkivska sentenced to 15 years imprisonment;
• Ivan Malyutsa, Roman Myhal and Yevhen Kachmarsky - 12 years imprisonment;
• Kateryna Zarytska - 8 years imprisonment;
• Yaroslav Rak and Yakiv Chorny - 7 years imprisonment.

The court also denied Hnatkivska, Malyutsa, Kachmarsky, Myhal, Chorny, Zarytska and Rak civil rights for 10 years.^{[citation needed]}

The actual assassin, Hryhorij Maciejko, never faced a judge; he died in Buenos Aires in 1966.^[5][6]

• Assassination of Gabriel Narutowicz, first interwar president, 1922