BEIJING (AP) — Police in Shanghai say they have detained a suspect in the case of the death by possible poisoning of the billionaire founder of a Chinese video game company that makes films based on the popular science fiction novel “The Three-Body Problem.”

Lin Qi, 39, died on Christmas Day after being hospitalized, according to his company, Yoozoo Games Co., also known as Youzu Interactive.

A police statement said a 39-year-old coworker, identified only by the surname Xu, was detained. The statement said the victim was hospitalized Dec. 17 and diagnosed with possible poisoning but gave no other details.

An employee who answered the phone Monday at the Shanghai police press office said there was no additional information to release.

The business magazine Caixin, citing unidentified industry sources, said the suspect is an employee of Yoozoo’s film division and was working on “The Three-Body Problem.”

Yoozoo also is know for its game “Game of Thrones: Winter Is Coming,” based on the popular TV series.

Lin ranked No. 870 among China’s richest entrepreneurs with a net worth of 6.8 billion yuan ($1 billion), according to Hurun Report, which follows China’s wealthy.