[2] His mother and brothers Isaac and Yacob died in Treblinka extermination camp; his father was killed in the Warsaw Ghetto Uprising of 1943.
He joined the Red Army during the Soviet counter-offensive and became an officer of the NKVD secret police in August 1944.
[3] Grajewski (pseudonym "Zamojski") was tasked with breaking up Polish anti-communist underground in the area of Zambrów.
A decade after his arrival Gray had become a tradesman in replicas of antiques according to what he wrote, doing business in the U.S., Canada and Cuba.
On 24 April 2016, three days before his 94th birthday, he was found dead in his swimming pool at his home in Ciney, Belgium, where he had lived since 2012.
'"[9] Pierre Vidal-Naquet, a French historian who first followed the idea of Gitta Sereny, has been persuaded by certificates provided by Martin Gray and withdrew his accusations against him.
[9] The Polish daily newspaper Nowiny Rzeszowskie (Rzeszów News) on 2 August 1990 published an interview with World War II Captain Wacław Kopisto, a soldier of the elite Polish Cichociemni unit, who took part in the raid on the Nazi German prison in Pińsk on 18 January 1943.