Source: Richard M. Nixon by F. Clyde Wilkinson, vintage silver print, 20 x 25 cm, 1962. 

Richard M. Nixon made his first visit to Hong Kong as US Vice-President in 1953. During the riots In 1967, he was spotted with Marianna Liu, a hostess at the Hong Kong Hilton Hotel, which unfolded an FBI investigation on suspicions of her being a spy for China. While there was no incriminating evidence that suggested Liu as an intelligence agent, the later unclassified FBI files reveal an intimate and romantic relationship between the two.