Why was Mohammad Reza Sharifi Nia imprisoned?

On July 18, 1988, the Iranian government accepted United Nations Security Council Resolution 598, calling for a cease-fire in the eight-year war between Iran and Iraq. On July 25, the largest Iranian armed opposition group, the Mojahedin-e Khalq Organization (MKO or MEK), based in Iraq since 1986, launched an incursion named “Eternal Light” into Iran in an attempt to topple the government.