Gerry Adams arrest: Sinn Féin claims 'dark side' to NI police
Sinn Féin's Martin McGuinness has claimed Gerry Adams' arrest is due to a "dark side" within policing conspiring with enemies of the peace process.
He added that the detention was a "deliberate attempt to influence the outcome of elections" in three weeks.
Prime Minister David Cameron said there had been "absolutely no political interference in this issue".
Northern Ireland First Minister Peter Robinson said it would be "political policing" if Mr Adams was not questioned.
BBC News NI Home Affairs Correspondent Vincent Kearney reports.