In November, two Chinese dissidents seeking sanctuary in Thailand, Jiang Yefei and Dong Guanping, were sent back to China despite having been recognized as refugees by the United Nations refugee agency. The Chinese police later said that the men had been in Thailand without authorization and were suspected of crimes involving illegal border crossing.

“The transfer procedure for the two was in accordance with a cooperation mechanism between Chinese and Thai police,” Xinhua, the official Chinese news agency, said, citing the police.

The spokesman for the Thai government could not be reached on Monday.

Panitan Wattanayagorn, an adviser to the deputy prime minister, said he was not aware of the disappearance of Mr. Li, the journalist. Speaking more generally about deportations, he said that Thailand had to be aware of and responsive to China’s rising influence in trade, investment and tourism.

“Several years ago, the number of Chinese tourists here was not even one million,” Mr. Panitan said. “Now it’s approaching 10 million.”

He emphasized that Thailand must continue to rely on the United States for security cooperation. In the military sphere, “The U.S. is still No. 1,” he said.

The Chinese government has said that suspects of crimes who return from abroad, including officials and their relatives accused of graft, have often come back voluntarily, offering extravagant contrition for their misdeeds. But critics say the secretive operations are likely to involve coercion and threats, if not outright force, and they point to the far-fetched accounts that detainees have given in the Chinese state-run news media.

Ms. He said her husband feared that if he was forced to go back to China, he would be punished for having publicly recounted the intense pressure that state security officers had used to recruit him as an informant against his colleagues and friends, and for having described censorship he witnessed in his job as an editor. He said the security agents had threatened to charge him with spying unless he agreed to act as an informant.