Egypt's Ministry of Interior has accused the Muslim Brotherhood organisation's Qatar branch of involvement in Sunday's bombing of St. Peter and St. Paul Church inside a Coptic cathedral complex in Cairo, which killed 24 and injured 49.
The interior ministry, in a statement broadcast on state TV Monday evening, said it has identified members of the "terrorist cell'' involved in the bombing, and traced their leadership to a branch of Egypt's Muslim Brotherhood group, which the state designates as a terrorist organisation, residing in Qatar.
The statement said that advanced investigation procedures led to the identification of fugitive Mohab Mostafa El-Sayed Kassem, whose militant code name is "The Doctor," as the lead man in the terrorist cell.
In a raid of cell's hideout in Cairo's Zeitoun district on Monday, police arrested four members, including a woman, according to the statement.
The arrested men were identified as Ramy Mohamed Abdel-Ghany, Mohamed Hamdy Abdel-Ghany and Mohsen El-Sayed Kassem—the brother of the cell's leader.
The woman was identified as Ola Hussein Ali, the wife of the accused Ramy Mohamed Abdel-Ghany.
The accused are believed to have aided the bomber who carried out the suicide attack on St. Peter and St. Paul Church and who was identified by authorities earlier on Monday as Mahmoud Shafiq Mostafa.
According to the ministry's statement, Kassem travelled to the Arab gulf state of Qatar in 2015, where he met with leaders of the Muslim Brotherhood (MB) organisation. He later returned to Egypt to lead a cell in carrying out terrorist attacks in the country, with full financial and logistical assistance from the MB organisation.
Upon directives from the MB in Qatar, Kassem communicated with members of Ansar Beit El-Maqdis terrorist group in North Sinai, moving there to receive training on the use of explosives.
After completing his training, Kassem was empowered by MB leaders in Qatar to carry out attacks against Egypt's Coptic Christians, with the aim of creating sectarian strife between Muslims and Christians in the country.
The interior ministry traced a statement to Kassem that called for carrying out attacks against Cairo's Coptic cathedral, on the basis that the church supports the current political regime.
The statement was issued on 5 December by a group calling itself "The Egyptian Revolutionary Council," which the ministry says is a political offshoot of the Muslim Brotherhood organisation.
According to the interior ministry, the statement reveals that Kassem worked on recruiting other men to his cell and received training in a terrorist hideout based in Zeitoun district in Cairo.
Among Kassem's cell members was the man implicated in Sunday's attack, Mahmoud Shafik Mohamed Mostafa, known by the militant code name" Abu Dagana El-Kinany."
Mostafa was apprehended in March 2014 for involvement in violent incidents related to the MB organisation and possession of firearms. He was released by court two months later.
Mostafa was later sought for arrest in two separate cases in 2015 and 2016, for terrorism-related activities and affiliation with a terrorist organisation.
The Ministry of Interior said that all apprehended members of the cell were referred to state security prosecution, while investigations are ongoing to find and arrest other members.
Sunday's bombing was the deadliest attack on Egyptian Christians in years, killing 24, many of whom were women and children.
In 2011, at least 23 Coptic Christians were killed in a suicide attack which targeted a New Year's Eve mass at the Two Saints Church in Alexandria.