Sayyid Ne’matullah Jazaeri Tustari writes in his Anware No’maniyyah, that a group of trustworthy men narrated to me that when Shah Isma’il Safawi gained control over Baghdad, he came to visit the Shrine of Imam Husayn (a.s.) in Karbala. He heard some people vilifying Hurr and hence came to the head of his grave and ordered it to be exhumed. People witnessed that Hurr was sleeping in his grave freshly drenched in his blood, and a kerchief was tied on his forehead.
Shah Isma’il tried to unfasten the kerchief from his forehead, which according to the historical reports was tied by Imam Husayn (a.s.). When the kerchief was untied, fresh blood started pouring out until the grave was filled with it. Then when the kerchief was tied at it’s place, the blood stopped. Then again they tried to untie that kerchief, but blood started pouring out. They tried to stop the blood by other means, but could not do so until they ultimately tied the same kerchief. Thus the fine status of Hurr was confirmed to them, and Shah ordered a mausoleum to be erected on his grave and appointed a servant to look after it.
Reference : Nafasul Mahmoom – Shaikh abbas Qummi (r.a.)