The Soviet government avoided the mention of Säre's name in any public sources, as he was suspected of treason by disclosing to Nazi Germany information about the Stalinist officials and pro-Soviet agents who had remained in German-occupied Estonia during the war.

[1] In 1921, he left Estonia for Soviet Russia and began his studies at a rabfak and later on the Communist University of the National Minorities of the West.

[1] He was sent back to Moscow and continued his studies at the International Lenin School and later on was sent to conduct illegal activities in countries like Britain, United States, Denmark and Sweden as a Comintern agent.

[3] He was arrested by the German occupiers and after extensive investigation he gave the information of his fellow underground communist officials and resistance fighters.

According to the researchers of the Estonian Institute of Historical Memory he was sent to Neuengamme concentration camp, where on 14 March 1945 he died as a result of heart failure.