The revered Sayyid, author of Farajal Mahmoom Fee Maarefate Nahjul Halaal wal Haraam Menan Nojoom says that he has met a number of people, who claim to have seen Imam Mahdi (a.s.) and some of them have also received letters from him:
“Thus, one of them who did not allow his name to be mentioned, says: I prayed to the Almighty Allah to give me the honor of seeing Imam Mahdi (a.s.). He dreamt that someone was saying: When it is time to see him, you will be signaled.
So when the time approached, he was in the shrine of Imam Moosa Kazim (a.s.). He heard the same voice he had heard reciting the Ziyarat at the grave of Imam Muhammad Taqi (a.s.). He went inside immediately and stood at the foot of the grave and with regard to the one about whom it was certain that only he is Imam Mahdi (a.s.) and is busy reciting the Ziyarat, when he came out, there was another person with him. But this man (narrator) could not speak to him, because of extreme humility.