45-year-old Xue Feng was detained in November 2007 on charges of attempting to acquire a database of information about China's oil industry.
A Beijing court found him guilty more than a year ago, but sentencing was been repeatedly delayed. on Monday, Jul 5, along with Xue other three Chinese nationals were also sentenced to prison.
According to the Xue's family, Xue has spent more than two years in jail and the state security agents tortured him by burning him with lit cigarettes on his arms.
Xue case first became public when an news agency reported about it in 2009. Even US President Barack Obama raised the case with President Hu Jintao during a state visit to Beijing in 2009.
Born in China, Xue earned a doctorate at the University of Chicago and became a US citizen, then he came back to his native country China to work.