 As the result the I-5 and I-6 projects were unified in 1929 under Polikarpov's leadership, although neither project met its specified completion date.Nikolai Polikarpov was arrested by the OGPU in September 1929 for the crime of industrial sabotage for these failures and sentenced to death, although this was commuted to ten years imprisonment in a labor camp.In December 1929 the OGPU gathered a number of aircraft engineers together at Butyrka prison, including Polikarpov, and formed the Internal Prison Design Bureau ("Konstruktorskoye Byuro Vnutrenniya Tyurma"—KB VT) under the leadership of Dmitry Pavlovich Grigorovich.