Mohammad bin Abu bakar role in killing uthman
Al-Jamiʿ al-Musnad al-Sahih, V3 p96
Khabar al-Mughirah ibn al-Akhnas ibn Shariq, p445
The report states that Muhammad ibn Abu Bakr came with thirteen men and reached Uthman. He seized Uthman by his beard. Muhammad then called upon a man from the group, who approached Uthman with a mishqas (مشقص) and struck him in the head. The report then states that they entered upon Uthman and killed him.
ثم جاء محمد بن أبي بكر في ثلاثة عشر رجلاً حتى انتهى إلى عثمان فأخذ بلحيته
قال: فأنا رأيته استعدى رجلاً من القوم بعينه فقام إليه بمشقص حتى وجأ به في رأسه فاشته ثم مر، قال: ثم دخلوا عليه والله حتى قتلوه
