On September 22, 1914, Sarkar and Marathé left for Washington, D.C. with a message for then German ambassador, Von Bernstorf. The latter got Von Papen, his Military Attaché, to arrange for steamers, purchase arms and ammunition, to be delivered on the eastern coast of India. On November 20, 1914, Viren sent Satyen Sen, V.G. Pingley and Kartâr Singh to Kolkata with a report for Jatindranath Mukherjee or Bagha Jatin. Bagha Jatin conveyed a note through Pingley and Kartar Singh to Rash Behari Bose asking him to expedite preparations for the proposed armed uprising.  In 1915, when Viren went to meet Raja Mahendra Pratap in Switzerland and convey him the Kaiser’s personal invitation, there was an attempt to murder Viren, while he was dogged by British agent, Donald Gullick.
With the failure of the Indo-German Zimmermann Plan, in 1917 Viren shifted the Berlin Committee to Stockholm. In 1918, he contacted the Russian leaders Troinovski and Angelica Balabanova, the First General Secretary of the Communist International. In December, he dissolved the Berlin Committee. In May 1919, he arranged for a secret meeting of Indian revolutionaries in Berlin. In November 1920, in his search of financial and political support exclusively for the revolutionary nationalist movement in India, he was encouraged by M.N. Roy (with Borodin’s approval).
Between 1931 and 1933, Viren went on advocating anti-Hitler activities, Asian emancipation from Western powers, independence of India, and Japanese intervention into Chinese revolution. Among his Korean, Japanese and Chinese friends was Zhou Enlai, the future Prime Minister of theCHINA .1936/37 at the department of ethnography of the Academy of Science in Leningrad. Viren was arrested on July 15, 1937. Death list with his name among 184 other persons was signed by Stalin, Molotov, Voroshilov, Zhdanov and Kaganovich on August 31, 1937. Death sentence was pronounced by Military Collegium of the Supreme Court of the USSR on September 2, 1937 and the same day he was shot.