Tabari and other historians recount “When the captives were brought to Yazid, Yahya ibn Hakam verbally reproached ‘Ubayd Allah ibn Ziyad for what he had done in two verses of poetry... but Yazid punched him on the chest and said, ‘Keep Quiet!’”34
This behavior, along with his obstinate defence and support of ‘Ubayd Allah ibn Ziyad, is a sign of approval that Yazid was pleased with him for killing Imam al-Husayn (as) and that it is highly likely that the crime of killing Imam al-Husayn (as) was carried out under direct orders from Yazid ibn Mu‘awiyah.
34. Ibn Athir, Al-Kamil fi al-Tarikh, vol. 3, p. 301; Tarikh Tabari, vol. 4, p. 252; Al-Bidayah wa al-Nihayah, vol. 8, p. 209.