The roof over a swimming pool collapsed Monday in Zhengzhou, Central China’s Henan province, killing three and injuring nine. Photo: Chen Liang/Caixin

Personnel from the city’s emergency management, public security, fire and health departments work at the site. Photo: VCG

An aerial view of the hole in the roof created by the collapse. Photo: IC Photo

Excavators and a crane stand by at the site. Photo: VCG

A total of 12 people were rescued from the site, the local government announced Monday in a Weibo post. Photo: Chen Liang/Caixin

The collapsed swimming pool is part of the Wuzhou Hotel, which has operated for more than 20 years. Photo: VCG

Cordon was set around the hotel after the incident. Photo: VCG

Police have controlled three related business operators. Investigation into the cause of the incident is underway. Photo: Chen Liang/Caixin

Residents watch the rescue work. Photo: Chen Liang/Caixin