An estimated 1,000 people were killed as Nigerian government forces fought Boko Haram in Borno, Yobe, Kano and Bauchi states in July and August of 2009.
But the footage obtained by Al Jazeera shows that many of the deaths occurred once the fighting was over.
Elements of the police and army staged a follow-up operation in which house-to-house searches were conducted and individuals were apparently selected at random and taken to a police station.
See link to video clip: http://english.aljazeera.net/news/africa/2010/02/2010298114949112.html