You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Umayyad_Caliphate

Context:
Early Muslim armies stayed in encampments away from cities because Umar feared that they might get attracted to wealth and luxury. In the process, they might turn away from the worship of God and start accumulating wealth and establishing dynasties. When Uthman ibn al-Affan became very old, Marwan I, a relative of Muawiyah I, slipped into the vacuum, became his secretary, slowly assumed more control and relaxed some of these restrictions. Marwan I had previously been excluded from positions of responsibility. In 656, Muhammad ibn Abi Bakr, the son of Abu Bakr, the adopted son of Ali ibn Abi Talib, and the great grandfather of Ja'far al-Sadiq, showed some Egyptians the house of Uthman ibn al-Affan. Later the Egyptians ended up killing Uthman ibn al-Affan.

Question:
What group murdered Uthman ibn al-Affan?

Egyptians