The sense of fear was heightened when Islamists rose to power following the 2011 uprising that ousted longtime autocrat Hosni Mubarak. The Khosoos dispute was the worst violence during the one-year rule of Islamist President Mohammed Morsi, who was removed in a popularly backed coup in July.
The fight started when young Muslims drew inflammatory symbols on an Islamic school and the vandalism was blamed on local Christians.
Two defense lawyers in the case said a cleric of the local mosque urged revenge for the death of the Muslim man, leading to three consecutive days of violence that also saw a church attacked and private shops and homes of Christians looted and burned. Assailants doused one of the Christians with gasoline and set him on fire. They contend that only two Christians were convicted in the case. The difference with the court's number of convicted could not be reconciled.
Samaan Youssef, one of the Christians' lawyers in the case told The Associated Press that the prosecution failed to identify any of the suspects in the killing of Christians because local witnesses were afraid to speak out and possibly provoke revenge attacks and renewed violence.
The violence later spread to the doorsteps of the country's main Coptic Cathedral after funerals for the Christian victims. An angry mob of Muslims threw firebombs and rocks at the church forcing a group of Christians, who attempted to march against the government, back into the church.
The violence left two dead, including one Christian. Reports at the scene said few police were present.
Iskandar Samir, another lawyer and relative of some of the defendants, said he would appeal the verdict. He described it as the "continuation of a series of sectarian rulings," adding that few Muslims are ever held responsible for violence against Christians.
Ishaq Ibrahim, a researcher at the Egyptian Initiative for Personal Rights, said investigations into the attack on the cathedral were never completed and no one stands charged. He lamented what he called selective justice in the case.
"This opens the door for more sectarian strife," he said. "The prosecution neglected the investigation."
Both the two lawyers and Ibrahim said one of those acquitted has been dead for five years, "raising questions about the prosecution's handling of the case."
With hundreds of people killed in the past three years of turmoil, rights groups have criticized prosecutors and police for weak evidence collection and shoddy prosecution. The groups say the weak process perpetuates a culture of impunity.