Authorities have put nine people, including staff of the developer and the contractor, under control over the building that collapsed in Shanghai's Minhang District, killing one worker.

The developer's bank account has also been put under control, the district government said.

District officials assured people who bought apartments in the collapsed building that they need not to worry about their investment.

"Buyers' money is safe," the information office of the Minhang government said on Sunday.

By noon of Sunday, at least 400 owners of apartments in the "Lotus Riverside" residential community had applied for refunds.

The owners set up a committee to handle negotiations with Shanghai Meidu Real Estate, which was developing the project, and the builder, Shanghai Zhongxin Construction Co.

A government task force with legal experts and officials from the local complaints authority had met 255 buyers by 5 pm on Sunday.

The community under construction has 629 apartments, with 489 of them sold.

Meanwhile, more than 300 residents evacuated after the under-construction residential building collapsed returned home with authorities assuring them their homes were safe.

The 132 households who live about 20 meters from the site of the collapse began to leave the three hotels where they had been staying at 5 pm Sunday after on-site checks said the homes were safe.

There was no indication of listing in the 10 remaining buildings in the community while checks also confirmed that water and gas supplies in the area were unaffected.

Experts in two on-site investigation committees set up by district authorities said they would be carrying out checks every two hours on all residential buildings in the area to make sure everything was safe.

They also took samples of concrete and reinforcing steel bars from the collapsed 13-floor building to test whether flaws in construction materials could be a factor in the incident in which one worker was killed.

Initial investigations showed that the weight of earth removed from beneath the building and dumped on a landfill area near a creek 30 meters away from the building had caused the river bank to collapse.

The earth was removed to build a garage under the building which toppled over, almost intact, at around 5:40 am on Saturday.

A 28-year-old migrant worker surnamed Xiao was killed. He was in the building collecting his tools when it collapsed around him.

Lotus Riverside has 11 13-story buildings with apartments ranging from 66 to 128 square meters. The average price of apartments in the collapsed building was 14,297 yuan (US$2,093) per square meter and 77 percent had been sold. The first phase of the estate had been sold and apartments in the second phase went on sale in April.

Shanghai Meidu Real Estate owns two other estates in the district, Luojin Garden which has 36 apartments, all sold, and Luojin New Garden, which has 207 for sale out of a total of 289.

(Shanghai Daily June 29, 2009)