On 4 July 1943 . Gralewski died in the 1943 Gibraltar B-24 crash , together with the Polish Prime Minister and commander-in-chief , Władysław Sikorski . Due to the controversy surrounding Sikorski 's death , some conspiracy theories surrounding this incident have raised questions regarding the role and fate of Gralewski in this incident , with suggestions by historians Dariusz Baliszewski and that he might have been shot by an assassin , and died ashore , not in the airplane crash , and that the assassin entered the airplane acting as his doppelganger . His wife , who after the war became a sociologist in the United States , wrote about her belief that he was murdered as a part of an assassination plot in her 1987 book '' Niezdemobilizowani '' . In late 2000s and early 2010s the Polish Institute of National Remembrance considered exhumation of Gralewski 's body to address this issue , but eventually decided against it
1943 Gibraltar B-24 crash
1943 Gibraltar B-24 crash
Jan Gralewski (courier)