Feliks Selmanowicz was arrested on 8 July 1946 in a conspirators’ flat in Sopot; three Security Office (UB) functionaries were said to have been killed during his attempted escape. He was then transported to a remand centre in Gdańsk and subjected to a brutal interrogation. He made a failed escape attempt. On 17 August the District Military Court in Gdańsk sentenced Second Lieutenant Selmanowicz to death. He was murdered on 28 August 1946 at 6.15 am in the cellar of the Gdańsk prison in Kurkowa Street, together with Danuta Siedzikówna alias Inka, a medic of the 5th Vilnius Brigade of the Home Army. Both of them cried “Long live Poland!” before their death.
The Provincial Court in Gdańsk cancelled the death sentence in 1997. In 2014, the Institute of National Remembrance (IPN) found the remains of Feliks Selmanowicz hidden by the communists under paving slabs at the Garrison Cemetery in Gdańsk. On 28 August 2016, a ceremonial state funeral of Zagończyk and Inka was held there to mark the 70th anniversary of the death sentence. President Andrzej Duda posthumously promoted Second Lieutenant Selmanowicz to lieutenant colonel.