HANGZHOU - One of the three IDTM doping control testers in the Sun Yang case said he was not a trained professional Doping Control Assistant (DCA), but a construction worker.

Three-time Olympic swimming champion Sun Yang declared his innocence at a Court of Arbitration for Sport (CAS) public hearing held in Montreux, Switzerland on November 15, after the World Anti-Doping Agency (WADA) appealed against him and swimming world governing body FINA over FINA's previous decision in favor of Sun on his alleged anti-doping rule violations.

The DCA, who insisted on anonymity, revealed he had provided his testimony by a written letter in Chinese to CAS and WADA several days before the public hearing.

"I am a builder and I am always busy at work, day and night. No one ever trained me about the doping test, and it is unnecessary for me to undertake such training."

"I agreed to give my words at a video conference before the public hearing as they requested. I was ready, but no one had ever contacted me about this," he said.

In an earlier interview with Xinhua in January, the DCA said he came to provide temporary help when asked by his middle school classmate, the DCO (Doping Control Officer) from WADA contractor IDTM, on the night of September 4, 2018.

The DCA noted that he and the DCO had not seen each other for a long time, having met at a middle school reunion dinner during the Spring Festival in February last year.