Pakistani authorities have detained the founder and former head of militant group Lashkar-e-Jhangvi Malik Ishaq at his home in Punjab province.
The group said that it carried out an attack in a Shia Muslim area of the southern city of Quetta last Saturday, which killed almost 90 people.
A heavy contingent of police surrounded Ishaq's residence and held negotiations with him, after which he gave himself over to the police, the BBC
Under public order laws, suspects can be held in Pakistan for three months without any charge.
Pakistani authorities have long been criticised for not taking enough action against groups such as LeJ that foment sectarian violence.