Chinese authorities have raided the offices of a company managing the dump site where a killer landslide left 76 people missing, while government records show the firm was not qualified to do the job.
A Reuters reporter saw police at two premises of Shenzhen Yixianglong Investment Development on Tuesday and no sign of employees.
At least one body has been recovered from the rubble after a giant deluge of mud and construction waste from the overfull dump site buried 33 buildings at an industrial park in the southern boomtown of Shenzhen on Sunday.
Thousands of workers were using sensors, drones and earth excavators at the 380,000-sq m disaster site, trying to reach possible survivors trapped under mud up to 10 metres deep. Overnight, the area was lit up with floodlights to allow uninterrupted rescue operations.
It was the second major man-made disaster in China in four months - in August, at least 160 people were killed in massive chemical blasts in the northern port city of Tianjin.
With growing worries about China's industrial safety standards and lack of oversight, Premier Li Keqiang ordered an investigation within hours into the mudslide in Shenzhen, a town that has boomed with the breakneck growth in the world's second-largest economy.
A central government meeting in Beijing overseen by President Xi Jinping that ended Tuesday said safety should be the "first priority" in China's city development and management, Xinhua news agency said.
"Safety awareness should permeate every aspect of urban work," it said.
Government records show that a company called Shenzhen Luwei Property Management won the right to manage the dump site within the Hengtaiyu industrial park in Shenzhen's Guangming New District in 2013.
But a company official told Reuters the rights were sold to another firm, Shenzhen Yixianglong Investment Development, for 750,000 yuan ($A161,110), before even winning the bid.
"They sought us out and contacted us first," said the employee, who said her name was Liu.
However, Yixianglong's business description registered with the government does not include logistics management as one of its areas of operation. This was a pre-requirement to bid for managing the site, according to bid documents.
A contract document between Luwei and Yixianglong, obtained by Reuters, showed that Yixianglong agreed to assume responsibility in the event of an accident.
Calls to Yixianglong went unanswered.
Shenzhen police declined to comment. The Shenzhen government did not respond to a request for comment.
