Shiite leader, Muhammad Ali, was gunned down at his Kano home today.
Police commissioner for Kano state, Ibrahim Idris, said he believed Boko Haram was responsible for the act.
In another development, police said a Southerner from the state of Osun was arrested for being a senior commander of the radical group.
His wife and five children were also arrested in a house stashed with weapoms like bombs, guns and ammunition, Idris said.
