Nigerian secret police have arrested an alleged spokesman for Boko Haram, a militant group that has claimed responsibility for attacks that have killed hundreds of people over the past two years.
Authorities said Wednesday they were questioning the suspect, who they say goes by the alias "Abu Qaqa."
"Abu Qaqa," or someone using the name, became a public facade for Boko Haram, frequently making telephone statements to the press following attacks, claiming responsibility and justifying them.
But authorities said that they are still trying to determine if the man they have in custody is the person behind those statements.
Boko Haram is believed to be behind scores of bombings and shootings, including a series of coordinated explosions in the northern city of Kano last month that killed at least 185 people, and a set of Christmas day attacks on several churches.
Jonathan has declared a state of emergency in parts of the north, the site of most of the violence.
Nigeria, Africa's most populous country, is divided between the mostly Muslim north and largely Christian south. The country has endured spates of sectarian violence over the years, though some of the conflict stems from economic and political factors as well.
Some information for this report was provided by AP, AFP and Reuters.