and thence to the Viceroy, who passed on an exaggerated summary, warning the Emir of a possible coup funded by the Germans and a threat to his life. In mid-1916, intelligence officers in Punjab captured letters sent by the Indian provisional government's Ubaidullah Sindhi to Mahmud al-Hasan, which were addressed to the Turkish authority and the Sharif of Mecca. The letters, written in Persian on silk cloth, were sewn into a messenger's clothing when he was betrayed in Punjab. The event was named the Silk Letter Conspiracy. In August 1915, Mahendra Pratap's private secretary, Harish Chandra, had returned to Switzerland after a visit to India, at which time he had carried messages to various Indian princes. He was captured in Europe in October 1915. Chandra divulged details of the Provisional Government of India and of the expedition. He also gave to British intelligence officers letters from Theobald von Bethmann Hollweg and Mahedra Pratap addressed to Indian princes. Subsequently, Chandra was sent as a double agent to the United States in 1917 to investigate and report on the revolutionary movement in Washington and the finances of the Ghadar Party. Also used as a double agent was a man by the name of Sissodia who claimed to be from a royal family of Rajputana; he attempted to infiltrate the Germans and the Berlin Committee in Zurich. Diplomatic measures The Afghan Emir was warned by New Delhi of the approach of the expedition even while efforts were underway to intercept it in the Persian desert. After it crossed into Afghanistan, the Emir was asked to arrest the members. However, Habibullah humoured the British without obeying the Viceroy's requests. He told the Viceroy that he intended to remain neutral and could not take any actions that were overtly pro-British. Indian intelligence became aware—after the expedition had already been in Kabul for some time—that they carried with them highly inflammatory letters from the Kaiser and the Turkish Sultan. Through British channels, the Russians voiced their concerns about the Emir's tolerance of the German presence and their intrigues with Pro-German Afghan counsellors. By December 1915, New Delhi felt it necessary to put more pressure on the Afghans. Communications between the British Empire and Kabul had been hitherto through the Viceroy at Delhi. Acutely aware of the pressure on Habibullah from his pro-German relatives and the strong anti-British feeling among the tribes, Viceroy Hardinge suggested that a