Eleven people were killed when a roof collapsed at a middle school gymnasium in China’s far northeast, authorities said on Monday. The incident occurred on Sunday in the city of Qiqihar and the last victim was pulled from the wreckage on Monday morning. The official Xinhua News Agency said construction work at the school was the likely cause, after workers stored materials on the gym’s roof that absorbed rain water.

Nineteen people had been in the gymnasium of the No. 34 Middle School, Xinhua said, but gave no details on how many were students. Social media and the Baidu news website carried footage of angry parents complaining about what they said was a lack of communication from authorities.