41-year-old Ban used to work as an official at the Haidian District Labor Insurance Bureau.

He sent a series of letters last year promising he would blow up the municipal government building and assassinate ten senior officials if his demands for a pay rise were not met.

The letters were sent to Beijing's mayor, the police chief and the Haidian district governor on April 15 and May 1, 2006.

He was later arrested on May 31, 2006. He now faces charges of issuing terror threats.

Ban decided to commit the crime because he was dissatisfied with the differences between his pay and the pay received by officials with his rank in other departments.