when Qays bin Masahir neared Kufa, Haseen bin Nameer stopped him so as to search him. Qays removed the letter of Imam and tore it, thus Haseen sent him to Ubaydullah. When he was made to stand facing Ubaydullah, he questioned him as to who he was. Qays replied, “I am one of the Shi’ah of the Commander of the faithful Imam Ali (a.s.) and his son.” He asked him as to why he tore the letter. Qays replied, “So that you may not be aware as to what was written therein.” Ubaydullah asked as to who had written it and to whom was is addressed to. Qays replied, “It was from Husayn bin Ali to a group of the people of Kufa, whose names I do not know.” Ubaydullah was infuriated and said, “You shall not go away from me until you reveal their names, or ascend the pulpit and curse Husayn bin Ali, his father and his brother, or else I shall separate each of your joints.” Qays replied, “I shall not reveal their names but am ready to curse.”
Saying this he ascended the pulpit and started praising and glorifying Allah. Then he offered salutations upon the Prophet (s.w.a.s.) and started praising Imam Ali (a.s.), Imam Hasan (a.s.) and Imam Husayn (a.s.) and asked for Allah’s abundant blessings to be bestowed upon them. Then he sent curses upon Ubaydullah, his father and all the oppressors of Bani Umayyah, from the beginning until the end. Then he said, “O people! I have been sent by Imam Husayn (a.s.) towards you and I have left him at such and such place, then respond to his call.” When Ubaydullah was informed as to what Qays said, he ordered that he should be thrown from the top of the palace. Thus he was martyred. (May Allah’s Mercy and Blessings be upon him).
Reference : Nafasul Mahmoom – Shaikh abbas Qummi (r.a.)