Eight suspected members of Islamist militant group Boko Haram confessed to involvement in the 2014 abduction of some 270 girls from Chibok, the Nigeria Police Force said.
The mass abduction caused global outrage and drew attention to the militant group which has killed more than 30,000 people since 2009 in an insurgency aimed at creating an Islamic state in north-east Nigeria.
Abba Kyari, deputy commissioner of police, said 22 suspected members of the militant group were arrested in different locations in the north-eastern states Yobe and Borno.
“Eight, including a commander, confessed to being involved in the planning and kidnap of the Chibok girls,” Kyari said.
“It was an intelligence-led operation. We have been monitoring them for about six months to a year,” said Kyari, who led the team.
Nigerian authorities this year convicted two alleged Boko Haram members to 15 and 20 years in prison for their purported role in the kidnapping.
The convictions are part of mass trials of more than 1,600 suspected members of the insurgency. Rights groups criticised the court hearings for their secretive nature, with initial trials held behind closed doors.
With presidential elections due in February, President Muhammadu Buhari’s administration is under pressure to show success in the fight against Boko Haram, a group he vowed to defeat when campaigning in 2015.
The government and military repeatedly said the insurgency has been defeated. Despite that, authorities do not control all the territory in Nigeria’s north-east, particularly around Lake Chad and militants frequently stage deadly attacks on the army and civilians.
Nigerian police are frequently accused of prisoner abuse and malpractice which they deny.
Many Chibok girls managed to escape in the hours following their abduction or were released in the last few years, including 82 released in an exchange deal including several imprisoned senior members of Boko Haram. Around 100 are still missing and their condition is unknown.