Yazid ordered the martyrdom of Imam Hussain–A confession by Ibn Zyad
Ibn Zyad himself said that Yazid ordered him to martyr Imam Hussain (May Allah be well pleased with him) on the threat of death. Imam Ibn Atheer (May Allah shower His mercy on him) records the confession of Ibn Zyad:
Translation: Now, about my martyring Hussain (May Allah be well pleased with him), the fact is that Yazid ordered me to do this. He threatened to kill me if I didn’t, so I martyred Imam Hussain (May Allah be well pleased with him). (Al Tarikh Al Kamil, Vol. 3, Pg No. 474)
According to Islamic Law, if any person murders anybody else, then as a punishment, the murderer is killed. But Yazid neither killed Ibn Zyad, Shimar or other officials nor dismissed them from their offices. Instead, he expressed his happiness. Afterwards, out of fear that the situation might go out of control, he expressed some sorrow in a formal, political manner. In fact, this wretched man used his stick to poke at the teeth of Imam Hussain (May Allah be well pleased with him), those teeth which the Holy Prophet (Sallallahu alaihi wa sallam) kissed.