The reconstructed roof of a 14th-century tower in eastern China partially collapsed in dramatic fashion this week, leading to an investigation and questions about whether the structure’s modern renovations had been substandard or even illegal.

Videos shared online showed tiles cascading off the roof of the Drum Tower in Fengyang County on Monday as dozens of people were gathered in an open plaza below. A large cloud of dust swelled around the building as the onlookers scattered.

No injuries were reported, according to the Fengyang government. It said the cause of the collapse was under investigation.

The tower has been designated a key cultural relic by Anhui Province, which includes Fengyang County. Its base, reportedly the largest of any drum tower in China, dates to 1375, during the Ming dynasty. Drum towers, often found in the center of Chinese cities, were historically used to help communities keep time.

But the building atop the base in Fengyang, which has curved eaves layered with tiles, was built only in 1995, the original having been destroyed in the 19th century. It was renovated last year, specifically to fix the problem of falling roof tiles, the Fengyang government said after the collapse.

That spurred questions online about the quality of the renovation, which cost about 3 million yuan, or nearly $420,000, and whether public funds had been misused. Ten years ago, the company that handled the tower project was renovating an ancestral hall in Anhui when a fire broke out that destroyed part of the building, according to state media reports.