HONG KONG - Twenty-seven officials in China have been "penalised" for the wrongful execution of a teenager 20 years ago, state news agency Xinhua reported late Sunday.

Hugjiltu was 18 in 1996 when he was sentenced and put to death for the rape and murder of a woman in the toilet of a textile factory in Hohhot in the Inner Mongolia Autonomous Region.

In 2014 Hugjiltu was finally exonerated after another man, Zhao Zhihong, confessed to the crime and was in turn convicted and sentenced to death.

"One of the blacklisted officials responsible for the wrongful conviction of Huugjiltu, Feng Zhiming, was suspected of job-related crimes and was subject to further investigation," Xinhua reported authorities as saying in a statement.

Feng, a former deputy chief with the public security bureau in Hohhot, could face prosecution, Xinhua added.

The other 26 - among them police officers and court officials - "received administrative penalties including admonitions and record of demerit", Xinhua said without giving further detail. The case has highlighted the shortcomings in China's Communist Party-controlled legal system, where acquittals are extremely rare - 99.93 percent of defendants in criminal cases were found guilty in 2013, according to official statistics. The use of force to extract confessions remains widespread in the country and defendants often do not have effective defence in criminal trials, leading to regular miscarriages of justice.

In the meanwhile, Chinese police have made their first statement on the fate of one of five missing Hong Kong booksellers, believed by many to have been abducted by mainland agents, acknowledging widespread concerns but offering no fresh information.

Lee Bo, 65, a dual British and Chinese national and owner of a publisher and bookstore specializing in books critical of China's Communist Party leaders, disappeared from Hong Kong on Dec 30. The disappearances have prompted fears that mainland Chinese authorities may be using shadowy tactics that erode the "one country, two systems" formula under which Hong Kong has been governed since its return to China from British rule in 1997.

In a rare but brief letter to Hong Kong media on Friday, police in the southern Chinese province of Guangdong offered no fresh information and did not address their Hong Kong counterparts' requests for a meeting with Lee, government radio station RTHK reported.

The letter repeated two points earlier released by the Hong Kong police - that Lee had sent a letter stating he went to the mainland on his own accord and that mainland authorities had confirmed to Hong Kong that he was "understood" to be on the mainland, RTHK reported.

"If there is news, we will notify (Hong Kong) in a timely fashion," it said. The British government is still waiting for responses to its diplomatic requests for information and access to Lee. Lee's wife visited him in a mainland guesthouse last weekend. She issued a statement saying he was healthy and in good spirits, and that he was a witness in an on-going investigation.

The four other booksellers are believed to be still in mainland detention, including Swedish national Gui Min-hai, who disappeared from the Thai resort town of Pattaya last October. He surfaced on Chinese state television this month, stating that he had voluntarily turned himself into Chinese authorities last month over a fatal drink driving case more than a decade ago. As international diplomatic concern intensifies, the European Union on Friday delivered some of its strong criticism yet of China's human rights record.