Camsing International, the Chinese firm that has owned the late Stan Lee’s Pow! Entertainment since 2017, has revealed that its founder and chairwoman Lo Ching has been detained by mainland Chinese authorities. The company’s shares crashed by more than 85% on Monday morning.

Camsing revealed Lo’s detention in a filing to the stock exchange in Hong Kong, where it is listed. It said that it became aware of her situation on Friday (July 5), and that she is being held “in criminal custody” by the Yangpu branch of the Shanghai Public Security Bureau.

“As at the date of this announcement, the directors are unable to ascertain the reasons of, or incidents leading to, the criminal custody of Ms. Lo. Nevertheless, as at the date of this announcement, the normal business operations of the Group and the functions of the Board both remained stable and have not been materially and adversely affected by the aforesaid event,” Camsing said in its filing.

Lo is also chair of another mainland-listed company Jiangsu Boxin Investing. In a regulatory filing to Chinese stock regulators, made after the close of trading on Friday evening, Boxin said that Lo and another executive, CFO Jiang Shaoyang had been detained Shanghai Public Security Bureau. While Boxin had received a certificate of their detention earlier that day, the company said that Lo had been detained on June 20, and Jiang taken in on June 25.

Camsing shares plunged by 86% on Monday, falling from HK$4.59 at their Friday close, to just HK$0.62 at the lunchtime trading break. Boxin shares initially fell from RMB12.28 on Friday to RMB11.00 in the morning trading session o the Shanghai stock exchange. But in the afternoon rebounded to RMB13.51.

Chinese authorities have previously taken into custody several prominent figures from the film industry. In December 2015 Guo Guangchang, chairman of the prominent conglomerate that owns Jeff Robinov’s Studio 8, and a major stake in Cirque du Soleil, was briefly detained and released without charge. Superstar actress Fan Bingbing was detained by the Public Security Bureau between late May and early October last year, before reemerging with a confession about her tax evasion. Li Ming, CEO of film production company Galloping Horse, died in custody in late 2013.

Camsing acquired POW! Entertainment in late 2017 and appointed Lee as its chief creative officer. It moved quickly to develop Lee’s brand and content in China, and last year held the first “Stan Lee (Shanghai) Comic Universe” convention at the Shanghai World Expo Exhibition Center.

After Lee’s death in November 2018, Camsing said it would “firmly push forward the development of Stan Lee IP and strive to integrate Stan Lee elements with Oriental tradition to realize Mr. Stan Lee’s great vision.”