Nongovernmental organization workers from Taiwan who travel to China should remain on a high state of alert, the commentary added. “You absolutely do not want to become the next Lee Ming-cheh,” it said.

In a letter to The Washington Post published on Sunday, Stanley Kao, Taiwan’s envoy to the United States, also connected the cases.

“Mr. Liu’s lifelong beliefs are the core values we live by in Taiwan, namely an abiding respect for human rights and due process of law,” Mr. Kao wrote, adding that China should immediately release Mr. Lee.

Beijing severed official communication channels with Taiwan in the fall after it became apparent that President Tsai Ing-wen, who took office in May last year, would not bow to Chinese pressure to endorse the “1992 consensus,” which holds that China and Taiwan agree there is “one China” — with each side reserving its own interpretation of what that means. Beijing has insisted that self-ruled Taiwan is part of its territory, and it has not renounced the use of force to achieve unification.

That has left the Tsai administration with limited tools to press Beijing for information about Mr. Lee. Ms. Tsai — one of the first government leaders to issue a statement mourning Mr. Liu’s death — has taken to her Twitter account to call for Mr. Lee’s release.

If history is any guide, progress on Mr. Lee’s case is unlikely in the coming weeks. The Chinese Communist Party is preparing for its 19th Party Congress this fall, a meeting that will determine the leadership lineup under President Xi Jinping for the next five years and influence the succession beyond that. In the jockeying for power, concessions to Taiwan could be interpreted as a sign of weakness.

Eeling Chiu, secretary general of the Taiwan Association for Human Rights, has supported Ms. Lee’s efforts to rally international pressure on China to free her husband. Ms. Chiu said that there had been no information about Mr. Lee’s situation aside from occasional statements from Beijing, such as the announcement last month that a lawyer had been appointed to represent him.