Adler was identified by Whittaker Chambers and Elizabeth Bentley as a Soviet spy and resigned from the Treasury Department in 1950.
After several years teaching at Cambridge University in England, he returned to China, where he resided from the 1960s to his death, working as a translator and economic advisor.
[10] When the United States re-established diplomatic contacts with China in 1971, Adler renewed his US citizenship [citation needed].
[13] A 1948 memo written by Anatoly Gorsky, a former NKVD rezident in Washington DC, identified Adler as a Soviet agent designated "Sax.
In addition to his contacts with US espionage groups, while he was serving as Treasury attache in China in 1944, Adler shared a house with Chinese Communist secret agent Chi Ch'ao-ting[15] and State Department officer John Stewart Service, who was arrested the next year in the Amerasia case.
Together with Harry Dexter White, Assistant Secretary of the Treasury, and V. Frank Coe, Director of the Treasury's Division of Monetary Research, Adler strongly opposed a gold loan program of $200 million to help the Chinese Nationalists control the inflation that took hold in unoccupied China during World War II.