Iran frees Chinese-American scholar for US-held scientist

This photo provided by the U.S. State Department, U.S. special representative for Iran, Brian Hook stands with Xiyue Wang in Zurich, Switzerland on Saturday, Dec. 7, 2019. In a trade conducted in Zurich, Iranian officials handed over Chinese-American graduate student Xiyue Wang, detained in Tehran since 2016, for scientist Massoud Soleimani, who had faced a federal trial in Georgia. (U.S. State Department via AP)

DUBAI, United Arab Emirates — A Princeton scholar detained for three years in Iran on widely criticized espionage charges was freed Saturday as part of a prisoner exchange that saw America release a detained Iranian scientist, a rare diplomatic breakthrough between Tehran and Washington after months of tensions.