However...
However, as the Islamic historians have written unanimously, Mu'awiya killed Hujr bin Adi and six of his companions, and one of them named Abdur Rahman bin Hannan Ghazzi was buried alive by Ziyad bin Abihi in Iraq. Mu'awiya's power and domination had assumed such proportions that he did what he liked and none could raise any objection.
Ali bin Husayn Mas'udi, one of the greatest Muslim historians and geographers of the 4th century writes thus in his book entitled Murujuz Zahab: At the time of return from the Battle of Siffin, a Kufian, mounted on a camel, came to Damascus. One of the Syrians disputed with him and said: "This she-camel which you have mounted is mine. It was looted in the Battle of Siffin and has fallen in your hands". Their dispute got prolonged and both of them went to Mu'awiya.
The man belonging to Damascus produced fifty witnesses, who deposed that the she-camel belonged to him. On the authority of the evidence given by fifty persons Mu'awiya also decided that the she-camel belonged to the Syrian and compelled the Iraqi to surrender it to him. The Iraqi said: "May Allah bless you. It is a he-camel and not a she-camel". Mu'awiya, however, said: "I have already given a decision and it cannot be altered".
When the people dispersed Mu'awiya called the Iraqi and asked him as to what his she-camel was worth. Then he gave him something more than the price of the he-camel and said to him: "Tell Ali that to fight against him I have 100,000 men, who do not distinguish between a he-camel and a she-camel" (i.e. if I say that a he-camel is a she-camel or vice versa, they will not dispute).
After narrating this story Mas'udi writes that Mu'awiya acquired such a grasp over the people that at the time of proceeding for the Battle of Siffin he called them to Friday prayers on Wednesday and offered Friday prayers with them, but none asked him as to why Friday prayers was being offered on that day when it was Wednesday.
Thereafter he has narrated another incident which we reproduce below in detail from the book entitled An-Nasayah al-Kafiya Li Mun Yatawalla Mu'awiya: Ammar Yasir was killed in the Battle of Siffin at the hands of Mu'awiya's men. As narrated by Bukhari in his Sahih, as well as by others, Ammar was striving more than others at the time of the construction of the Masjid of Madina and when the Holy Prophet saw him he said: "Alas! Ammar!