With the largest number of Internet users in the world, China is an irresistible market for U.S. tech companies. But it’s also proved to be a tricky place to do business. The Chinese government monitors and censors its citizens online, and a number of U.S. corporations have been accused of helping.

The most recent company in the spotlight is Cisco Systems, Inc., a leading provider of the routers and pipelines that help drive the Internet. The San Jose–based company has been sued by plaintiffs in two states this year. Both were brought by Chinese dissidents who allege that they were tracked, tortured, and imprisoned as a direct result of Cisco’s collusion with Chinese authorities.