There will be a time of occultation when Hazrat Mahdi (as) will be unseen by people. During this time, people will think that Hazrat Mahdi (as) has vanished, and some even think that he is dead. This is revealed in the hadith handed down from our Prophet (saas):
THERE WILL BE TWO DISAPPEARANCES OF THE QAIM [HAZRAT MAHDI (AS)]. ONE WILL BE LONGER THAN THE OTHER...
(Sheikh Muhammad bin Ibrahim Nomani, al-Ghaybah al-Nomani, p. 199)
The lord of this rising [Hazrat Mahdi (as)] will disappear two times. ONE DISAPPEARANCE (PERIOD OF IMPRISONMENT) will be so long that THEY WILL SAY, “He is dead.” Some will say, “He has been killed.” Others will say, “He has gone...”
(Sheikh Muhammad bin Ibrahim Nomani, al-Ghaybah al-Nomani. 198)
... EVENTUALLY, ONE OF MY CHILDREN [HAZRAT MAHDI (AS)] WILL DISAPPEAR FROM PEOPLE’S SIGHT. PEOPLE WILL SAY THAT HE HAS DISAPPEARED, BEEN KILLED OR DIED. THEN CORRUPTION WILL BE BORN AND SCOURGES WILL APPEAR. ETHNIC BIGOTRY WILL BE RESURRECTED, AND PEOPLE WILL LOSE THE WAY OF THE RELIGION.
(Sheikh Muhammad bin Ibrahim Nomani, al-Ghaybah al-Nomani, p. 163)
Our Prophet’s (saas) words: “...THEN CORRUPTION WILL BE BORN AND SCOURGES WILL APPEAR. ETHNIC BIGOTRY WILL BE RESURRECTED, AND PEOPLE WILL LOSE THE WAY OF THE RELIGION” refer to a time around 1400 (1979-1980), according to the Islamic calendar, of great disorder and corruption in society, when people turn aside from religious moral values and deviate into Marxist, communist, atheist and Darwinist thinking. Indeed, the 1980s were a time, especially in Turkey, of great anarchy, terror, disorder and insecurity, when people were afraid for their lives and property, and when they turned their backs on Islam. PKK terror was responsible for great corruption in the form of Kurdish-Turkish divisions, giving birth to a spirit of tribalism in society. People were turned away from the warm, peaceful and loving spirit of Islam and encouraged to adopt Darwinist thinking. With the appearance of Hazrat Mahdi (as), however, Allah will intellectually annihilate these ideologies, and belief in Allah will spread rapidly throughout the world.