There was extreme repression at the time of Imam al-Askari, especially due to fact that the awaited Imam al-Mahdi was to be born to this Imam. Those who had usurped the right of the caliphate from the Imams feared for their life and position while the Shias awaited his birth. Therefore, the Imam was kept under strict supervision. The Imam was constantly transferred from one prison to the other.
On one such occasion while he was a prisoner in Baghdad there was a severe drought. People were facing a famine. People didn't know what to do until a Christian priest came forward, lifted his hands in prayer and rain fell. The Caliph became worried he came to the Imam and asked to help lest the people forsake Islam for Christianity.
The Imam was allowed to leave the prison to go where the crowd assembled to see the miracle performed by the priest. The Imam stood there with the crowd and when the priest raised his hands for prayer and rain began to fall, Imam told one of his companions to seize the hands of the priest and bring the piece of bone hidden in his hands.
When this bone was brought before the Imam, he said that it was the bone of a Prophet of God. It was the effect of this holy bone when lifted in prayers to God that brought God’s mercy and brought rain to the land. This way the Imam lifted the doubts from the minds of the people. After this, the Imam himself spread his prayer mat and performed two Rak’ats of prayers then lifted his bare hands to God for the rain to come to the land and wipe out the draught.
Fearing Imam’s popularity, the Abbasid caliph Mu’tamid poisoned the Imam at the age of 28.
We ask Allah to hasten the reappearance of his son, the one who will establish justice and avenge the blood of the oppressed.