 Complete the following phrase:  He was born in Buraków in Gmina Łomianki. A metal worker, he joined the Social Democratic Party of the Kingdom of Poland and Lithuania SDPiL, which was led by Rosa Luxemburg and Leo Jogiches, in 1904 in Zakopane in the Austrian ruled part of Poland. As an active party member, he was arrested eight times, and spent four years in prison. In 1910, he emigrated to the US, where he joined a group of Polish social democratic workers. He moved to Russia in 1912. After the February Revolution, in 1917, he set up a social democrat organisation among exiled Polish workers in Tiflis, in Georgia, and was elected to the Tiflis soviet. In 1918, he joined the Communist Party CP of Belorussia Belarus, and was arrested while Belarus was under German occupation. but soon escaped and moved to Grodno, where he was elected chairman of the Grodno CP, and of the Grodno soviet. In 1919, he was elected to the Central Committee of the Communist Party of Lithuania and Belorussia. In 1921 - after the Soviet government had recognised Lithuanias independence - he was appointed a secretary of the Belorussian CP. In 1924, he was Belorussian Peoples Commissar for the Interior, but later that year. was transferred to the Polish section of Comintern, and appointed a candidate member of Cominterns Praesidium, and represented Comintern at congresses of the Polish CP in the late 1920s. He was a member of the Central Committee of the Polish Communist Party from 1925 to 1930. In 1930-37, he worked in the office the Chief Prosecutor of the USSR. He was arrested in September 1937, during the 