A former manager at the developer behind the hugely popular mobile game Game of War has been arrested for allegedly stealing "trade secrets," The Wall Street Journal reports.

42-year-old Jing Zeng was detained by FBI agents on August 20 as he attempted to board a plane for Beijing, China, according to federal documents obtained by the publication.

Zeng is accused of stealing data from a computer at developer Machine Zone; the information he attempted to make off with reportedly pertained to in-game player behavior, including details about how players spend money--but not actual source code. Still, this type of information would theoretically be very valuable, given how big and successful Game of War is.

"The data Mr. Zeng allegedly stole 'provide valuable insight and a huge competitive advantage over other online game providers and competitors,'" according to the unsealed documents. There is no mention in the complaint regarding what Zeng intended to do with the stolen data.

Machine Zone, based in Palo Alto, California, is best known for its top-grossing strategy game, Game of War. Advertisements for the game, including one that aired during the Super Bowl, feature model Kate Upton.

According to his LinkedIn page, Zeng joined Machine Zone in November 2014 as a director, and left in July this year. The Wall Street Journal reports that Zeng became unhappy with his role at Machine Zone earlier this spring; he reportedly wanted to change internal teams, but his request was denied.

Zeng's bosses then reportedly told him he needed to leave the company. It was at this time that Zeng started to download the files "from a proprietary company database," according to the complaint.

But the story didn't end there. Per The Wall Street Journal:

"Confronted by company executives, Mr. Zeng tried to use the files as a bargaining chip for a severance agreement, according to the complaint. The company appeared open to a three-month package, while Mr. Zeng wanted six or seven months, the complaint said. He then allegedly gave conflicting accounts of how many copies he made and whether some of the storage devices holding the files were in China or San Ramon. The company, in the meantime, contacted the Federal Bureau of Investigation. Agents arrested him as he tried to board a flight Aug. 20."

We'll have more on this story as it becomes available.