The Nigerian army said that Babuji Ya’ari was actively involved in the mass abduction of schoolgirls in Chibok and his arrest led to arrest of some female members of Boko Haram.
The rebels shot dead their victims after looting homes and shops and setting fire to buildings, said Debiro Hawul resident Umaru Markus.
Two teenage girls blew themselves up near a crowded mosque in Maiduguri, killing 30. This is the fourth suicide attack in June by Boko Haram.
Boko Haram took control of a large swath of northeast Nigeria until a multinational force this year forced them out of towns and villages.
Local authorities say the victims probably died several months ago and their remains have only now come to light.
Nigeria police said four other people were injured in the attack.
The explosion was timed to go off as merchants were closing shop, others were hurrying to make last-minute purchases and commuters were catching tricycle taxis home.
Nigeria’s Ministry of Defense denounced the report as “biased” and another attempt by the organization to “blackmail” the military hierarchy.
The Nigerian military must be investigated for participating in, sanctioning or failing to prevent the deaths of more than 8,000 people murdered, suffocated, and tortured to death,” the report said.
An armed fighter with his face covered by a scarf claims Boko Haram still holds several northeastern towns, It says thousands of fighters remain in a north-eastern forest stronghold.
The explosion on Saturday killed people who were prostrating themselves for afternoon prayers outside the mosque, including traders from the nearby crowded marketplace in the largest city in Nigeria’s troubled northeast, survivors said.
According to a nurse, five bodies were brought to the hospital mortuary and 15 wounded people are being treated.
It is unclear if those rescued include the schoolgirls kidnapped a year ago from a boarding school in Chibok town.
The women were exhausted, too traumatized to realize they were safe, or be questioned about their experiences under Boko Haram
Nigerian Army rescued another 234 women, girls and children from Boko Haram in the remote Sambisa Forest.