A Chinese man who graduated from a Taiwan university has been detained on suspicion of spying for China, the first known case of a Chinese student being investigated for espionage since 2011, local media reported Saturday.

Reports quoted prosecutors as saying that the former student, Zhou Hongxu, is being held incommunicado on suspicion of recruiting people to develop a spy ring in Taiwan.

Prosecutors alleged that Zhou, 29, tried to recruit an official of the Foreign Ministry by offering him a free trip to Japan in exchange for delivering classified materials.