Commercial satellite photography taken in early April at a building in the Parchin military complex, an Iranian nuclear site widely suspected of engaging in nuclear weapons-related research, shows activity suggesting that Iran is trying to wash the building to remove evidence of nuclear weapons research . . . Iran has denied repeated requests by inspectors from the International Atomic Energy Agency (IAEA) to access this site and speak with scientists working there . . . Iran may be trying to clean this building before allowing an IAEA team to visit . . . in 2004, Iran razed a research building near Lavisan and removed a layer of earth near the facility presumably to hide evidence of nuclear weapons research . . . Iran is believed to have conducted explosive testing that may have been related to nuclear warhead research at Parchin, but most of the nuclear work conducted there is unknown to the West and the IAEA.