The leader of an Islamic sect blamed for days of deadly violence in Nigeria has been killed in police custody, police officials say. The news came just hours after security forces said they had captured Mohammed Yusuf in the city of Maiduguri. Mr Yusuf led Boko Haram, which wants to overthrow the government and impose a strict version of Islamic law. Hundreds of people have died in five days of clashes between his followers and security forces. "He has been killed. You can come and see his body at the state police command headquarters," Isa Azare, spokesman for the Maiduguri police command, told Reuters news agency. His bullet-riddled body was shown on state television, AFP news agency said. Troops had stormed Boko Haram's stronghold on Wednesday night, killing many of the militants and forcing others to flee. Mr Yusuf was arrested earlier on Thursday, after reportedly being found hiding in a goat pen at his parents-in-law's house. BBC News website Africa editor Joseph Winter says Nigeria's security forces have a terrible reputation for brutality and human rights groups accuse them of frequent extra-judicial killings. 'Gun battles' The violence began on Sunday night in Bauchi state, before spreading to other towns and cities in the northeast of the west African nation. Crowds of militants tried to storm government buildings and the city's police headquarters, but dozens of them were shot dead by security forces. Several days of gun battles between militants and Nigerian security forces ensued, culminating in the assault on the militant's stronghold. It is thought more than 300 people have died in the violence - some estimates say 600, although there has been no official confirmation. The Red Cross said about 3,500 people had fled the fighting and were being housed in their camp. Witnesses and human rights groups have accused the military of excessive violence in quelling the militants, but the army says it used a minimal amount of force. Police say Mr Yusuf was a 39-year-old preacher from Yobe state, who had four wives and 12 children. They described him as a motivational character. His sect, Boko Haram, is against Western education. It believes Nigeria's government is being corrupted by Western ideas and wants to see Islamic law imposed across Nigeria. Sharia law is in place across northern Nigeria, but there is no history of al-Qaeda-linked violence. The country's 150 million people are split almost equally between Muslims in the north and Christians in the south. Source: BBC