Cairo - Egyptian authorities have detained three people suspected of planning and carrying out a Cairo police checkpoint bombing that killed six policemen last month, the interior ministry said on Thursday.
In footage published by the interior ministry, one of the suspects, Mahmoud Ahmed Mohamed Ahmed, confessed he planted an explosive device at the checkpoint on December 9 in Cairo's Al-Haram street.
Investigations showed the perpetrators belonged to the newly-emerged Hassam Movement, the ministry said.
Hassam had claimed responsibility for the attack.
The two others arrested are members of the group operating its hideouts and handling its logistics, the ministry said.
Authorities located hideouts for the group in Cairo's October 6 district, the ministry added.
During raids by security forces on these hideouts, another suspect was killed in a gunfight, while police found items including footage recorded while the attackers were monitoring the checkpoint ahead of the bombing, according to the ministry.
In the video confession, the suspect Ahmed said he joined the Muslim Brotherhood in 2015, and in mid-2016 he was told his subgroup had joined Hassam.
After monitoring policemen's homes and security convoys, the group scoped out the Al-Haram street checkpoint before planning their attack.
On the day of the explosion, the attackers moved close to the checkpoint and pretended their car had broken down. Ahmed placed an explosive device shaped like a rock near the checkpoint before another attacker set it off as they left in their car, he said in the video confession.
Attacks on security forces have escalated since the military's July 2013 ouster of former Islamist president Mohamed Morsi, who hails from the Muslim Brotherhood group, and a crackdown on Islamists.
Analysts had warned that Islamists affiliated with the Brotherhood, though not necessarily under their control, could step up violence in the face of the crackdown.
Militants in North Sinai province, at the heart of an insurgency against security forces, pledged allegiance to the Islamic State jihadist group in November 2014.
Most attacks in Cairo have been claimed by Hassam and another little-known group, Lawaa al-Thawra.
ISIS claimed responsibility for a December 11 bomb attack inside a Cairo church that killed 27 people.