Iranian President Hassan Rouhani participated Monday in the ceremony mounted to honor the Knowledge, the revolutionary contribution, and the Rank of the late Ayatollah Seyyed Mostafa Khomeini in Tehran. Seyyed Mostafa Khomeini, the eldest son of the late Imam Khomeini, suspiciously passed away in 1977 in Iraqi city of Najaf. Many surmise that his death was conspired by the intelligence service of Iranian monarch regime of Pahlavi.