Maritime security experts say the Humanity likely went “dark” as it was preparing to offload its cargo of Iranian oil in a ship-to-ship transfer to a waiting middleman. For decades, the EOPL has served as an unofficial marketplace for sanctioned Iranian, Russian and Venezuelan oil, analysts say. Another Iranian oil tanker, the Dore, could be seen sailing through the Strait of Malacca towards the Middle East on Thursday and may have recently departed the area. China does not officially acknowledge purchases of Iranian oil, and a spokesperson at the Chinese embassy in Washington, DC told Al Jazeera they were unfamiliar with the transit of Iranian oil through the EOPL to China. However, Chinese customs data offer some clues about the origin and movement of cargoes through the EOPL, according to Downs of Columbia University.