Shanghai authorities said a suspect in the death by possible poisoning of a China video game business owner is in custody, The Associated Press reported Tuesday.

Yoozoo Group chief executive officer Lin Qi, 39, died Christmas Day. Police suspect a colleague had plotted to poison him.

Lin's company is known for its Game of Thrones: Winter Is Coming video for mobile phones and desktop computers. The game is adapted from the HBO TV series.

Yoozoo also jointly publishes Supercell's video game Brawl Stars with Tencent Holdings in China.

Based on a statement by the Shanghai police, a 39-year-old colleague identified only as Xu, had been detained.

Business publication Caixin, quoting unnamed sources, said Xu was an employee of Yoozoo's film and TV unit and was working on the China sci-fi trilogy "The Three-Body Problem" to which Lin'z company acquired the rights in 2015.

In September, Netflix said it would adapt the bestselling books into an English series with Game of Thrones creators D.B. Weiss and David Benioff. Lin was the executive producer.

Alleged infighting at Yoozoo may have been the motive for the poisoning of Lin, according to reports.

Lin fell ill last week and was hospitalized Dec. 17. He showed symptoms of an "acute illness," reports said.

Lin was in intensive care and had to be resuscitated after his heart stopped, sources said.

Shares of Yoozoo dropped by as much as 18% since Lin was hospitalized and retreated for the second consecutive day Dec. 25 in Shenzhen by almost 10% to an intraday low of 12.71 yuan.

Lin, who founded Yoozoo in 2009, was China's 870th wealthiest person with a net value of almost 7 billion yuan ($1.1 billion), based on the Hurun Report, which tracks the country's richest.