Shanghai mayor Han Zheng Monday has called for a thorough investigation into the residential building collapse on June 27 and urged authorities to publicize the findings soon.
Calling the collapse a "major accident", Han said all parties responsible should be "punished severely".
A 13-story under construction apartment building in Shanghai's Lotus Riverside complex fell to its side, almost intact, on June 27, killing one worker.
A preliminary investigation revealed that "pressure imbalance on two sides of the structure" caused the building to collapse. The investigation report did not mention the parties responsible.
Media reports earlier said the digging to construct an underground car park on the north side of the building weakened the structure's foundation.
The real estate developer is also blamed for heaping a mound of soil up to 10 meters high on the other side.