Shares of Ambow, a Chinese education company, fell more than 12 percent in morning trading.
PricewaterhouseCoopers Zhong Tian CPAs Ltd. sent a letter to Ambow stating that it was concerned that the investigation may not be getting the necessary resources and time.
Fenwick & West LLP, which also resigned as counsel to the audit committee, has been conducting an investigation since July over the claims of the former employee, who also cited improper conduct by Ambow in relation to its acquisition of a training school, and a number of other issues.
The investigation is ongoing.
Shares of Ambow Education Holding Ltd. dropped 15 cents to $1.03.