TAIPEI (Taiwan News) — The soldier who swam from a small outlying island in Kinmen County to China has been interrogated by three separate Chinese government units, the head of Taiwan’s top intelligence agency said Wednesday (March 22).

Chen Chia-hsun (陳嘉壎) missed the March 9 morning roll call on the island of Erdan, less than 5 kilometers from the coast of the Chinese province of Fujian. While speculation initially focused on an accident, it soon became clear that Chen had swum away voluntarily and had been picked out of the water by the Chinese authorities.

Responding to questions from lawmakers at the Legislative Yuan on Wednesday, National Security Bureau (NSB) Director-General Tsai Ming-yen (蔡明彥) said that the soldier had been interrogated by three separate Chinese government units in Xiamen, CNA reported. However, he was not willing to divulge the nature of those units as that would compromise the sources of his intelligence.

The intelligence chief repeated assertions by other Taiwan government officials that Chen’s rank was low, and he was therefore not at risk of betraying useful confidential information about the frontline island to China.

Prosecutors in Kinmen County issued a warrant for Chen’s arrest, with the Ministry of Justice (MOJ) applying to have him extradited from China. The Mainland Affairs Council (MAC) told legislators the process could take some time, citing the example of two Chinese who were picked up in Kinmen and Taichung in May last year and returned to China in January.

Chen reportedly did not want to return to Taiwan, but the decision was in the hands of the Chinese authorities, the MAC said. The soldier was likely to be charged in China with illegal entry, which was covered under judicial cooperation agreements between the two sides, allowing extradition to Taiwan.