Tsai Chin-shu, a scholar from Taiwan, has been sentenced to four years in prison on espionage charges by Chinese mainland authorities, according to Zhu Fenglian, spokeswoman for the State Council Taiwan Affairs Office, during a press conference in Beijing on Wednesday.

Tsai, formerly the chairman of the South Taiwan Cross-Strait Relations Association, had been under investigation by mainland authorities since July 2018 on suspicions of engaging in activities that threatened national security.

Zhu emphasized that all aspects of Tsai's sentencing have been conducted in strict adherence to the law. She also addressed previous media reports suggesting Tsai's disappearance, asserting that mainland authorities had duly notified Tsai's family, dispelling any claims of him being "missing."

The relevant authorities have rigorously followed legal procedures while handling Tsai's case, and they have safeguarded all his lawful rights in accordance with the law, she said.