FILE PHOTO: Israeli Prime Minister Benjamin Netanyahu stands by a screen with an image of Iranian nuclear scientist Mohsen Fakhrizadeh during a news conference at the Ministry of Defence in Tel Aviv, Israel, April 30, 2018. Picture taken April 30, 2018. REUTERS/ Amir Cohen/File Photo
Iranian scientist Mohsen Fakhrizadeh, who was killed on Friday, led a life of such secrecy that even his age was under wraps but much about the clandestine nuclear weapons programme he is believed to have run has long been known.