"I can't lose my best friend," Amanda Thayer, a friend of Watts, said of her disappearance.
Xuecheng's case is one of the most prominent since the #MeToo movement took hold in China.
The CNR civil engineering society said structures dating from when the bridge was built had surpassed their lifespan.
Williams resigned one day after the confrontation, which was captured on video and went viral.
NATO ally Turkey has accused Washington of waging an "economic war" as part of a plot to harm the country.