In most of the accounts that have come down to us, an impression is created that Uthman was killed because he unduly shielded Marwan. It is related that the delegation which came from Egypt merely complained against Abdullah b Sa'ad the Governor of Egypt. Uthman wrote a strong letter to Abdullah b Sa 'ad to redress the grievances of the people. It is alleged that Abdullah b Sa'ad instead of redressing the grievances of the people scourged the persons who had complained against him, and had one of them executed. Thereupon the Egyptians came to Madina for the second time. They saw some of the Companions, and explained their grievances to them. It is reported that Talha b Ubaidullah saw Uthman and spoke some harsh words to him about the laxity of his administration. Ayesha is also reported to have criticized Uthman. Ali is reported to have advised Uthman to depose Abdullah b Sa'ad from the Governorship of Egypt. Uthman agreed to the demand, and wanted the Egyptians to name the person whom they wanted to be appointed as the Governor of Egypt. They suggested Muhammad b Abu Bakr, and Uthman passed orders deposing Abdullah b Sa'ad and appointing Muhammad b Abu Bakr in his place. The Egyptians felt satisfied at this order and they returned to Egypt. After they had proceeded a few stages from Madina they came across a slave of Uthman. On search he was found carrying a letter to Abdullah b Sa'ad not to give effect to the orders of deposition passed against him. He was instructed to put the rioters to death. That made the Egyptians return to Madina. They saw Ali and Ali took them to Uthman. Uthman took a solemn oath denying all knowledge about the letter. It was suspected that the letter was in the hand of Marwan. The Egyptians wanted that Marwan should be handed over to them. Uthman refused, and thereupon the rioters besieged Uthman in his house. The siege lasted for some days and ultimately Uthman was martyred. It is alleged that when Ali heard of the murder of Uthman he said that he wanted the murder of Marwan and not that of Uthman. This account tends to give the impression that Uthman lost his life because he showed undue favor to Marwan
Research has established that the story about the alleged letter is a concocted story, and is remote from reality. It appears from Tabari that when the rioters came to Madina, Abdullah be Sa'ad was ousted from power by a revolt led by Muhammad b Abi Hudhaifa. Muhammad b Abi Hudhaifa was opposed to Uthman, and as such there was no occasion to require that the rioters should be murdered.
Even if the story of the letter were true, Marwan who was the Minister could not be handed over to the rioters merely because they suspected that he had written the letter. Marwan could not be condemned unless a regular trial was held and he was found guilty. If the rioters had demanded the trial of Marwan, Othrnan would have agreed to such a trial, but he could not hand over a high functionary of the State to the fury of the rioters without trial.