Andrew Jacobs / New York Times News Service

BEIJING — A brief news article published Sunday by a score of state-run news media outlets offered an account of an unexpected judicial verdict: A Beijing municipal court had sentenced 10 people to jail for illegally detaining and assaulting a group of citizens who had come to the capital to lodge complaints about official malfeasance in their hometown in Henan province.

The defendants had flashed government identification cards when they rounded up the 12 petitioners and bundled them off to a secret “black jail” on the outskirts of the capital, according to The Beijing Youth Daily, the first paper to publish the news.

Legal rights advocates hailed the landmark court decision, said to be the first of its kind in any such a case in the capital, as did many users of Sina Weibo, the Chinese equivalent of Twitter. “Great news,” wrote one. “This is the start of rule of law.”

But apparently the news was too politically discomfiting to survive. By the end of the day, the article had been deleted from most websites, and a court employee insisted that news accounts of the verdict were false. The Beijing Youth Daily, the court employee said, had agreed to publish an apology.

No apology had appeared on the newspaper’s website by late Sunday.

At first glance, the episode appeared to highlight imperfections in the Communist Party’s propaganda machine: If the news was untrue, why did tightly controlled media outlets, including People’s Daily and the Xinhua news agency, publish it?

But it also underscored official ambivalence over an extralegal form of detention that has drawn criticism from rights activists and outraged many Chinese.