BEIJING, May 9 -- The Cyberspace Administration of China (CAC) on Monday demanded an overhaul of China's leading search-engine Baidu following an investigation.

The CAC said Baidu relied excessively on profits from paid listings in search results, and did not clearly label such listings as the result of commercial promotion, compromising the objectivity and impartiality of search results.

Like other search engines, Baidu sells links that appear in search results. The more an advertiser pays, the higher it will appear in the search results. The public are likely to be misled by the search results they find on Baidu, the CAC said.

NASDAQ-listed Baidu was already in the eye of a public-relations storm after the death of Wei Zexi, 21, a computer science major at Xidian University in northwest China's Shaanxi Province.

Wei was diagnosed with synovial sarcoma, a rare form of cancer, in 2014 and had been undergoing a controversial cancer treatment advertised on Baidu, at the Second Hospital of Beijing Armed Police Corps, which the Wei family also found through a Baidu search. The treatment was unsuccessful and Wei died on April 12.

In February, on question-and-answer website Zhihu, a Chinese version of Quora, Wei directly accused Baidu of being at least partly to blame for his troubles. The anger of netizens who claim the search engine does not properly check the credentials of advertisers has been growing ever since.