LAGOS: Nigerian authorities have arrested the brother of an ex-militant leader implicated in recent deadly car bombings, alleging he is behind threats on behalf of Mend rebels, security sources.

Charles Okah is the brother of Henry Okah, the former leader of the Movement for the Emancipation of the Niger Delta (Mend) arrested in South Africa the day after the October 1 independence day twin blasts. He is accused of playing a key role in the bombings that killed at least 12 people.

Charles Okah was arrested on Saturday in Lagos. His wife, Angela, confirmed the arrest and said four others - Okah's son, Boloebi, 23, his son's friend, Sola Ladoja, a house aide, and a friend - were also taken into custody.

Angela Uchechi Okah denied her husband had any role in Mend activities and said she had not been able to contact him since his arrest.

Charles Okah "was arrested after the bomb alert e-mails and smses were traced to him," a source told AFP. He said authorities suspected he was a Mend spokesman.

Nigeria's intelligence agency and police could not be reached for commen