Short clip shows unidentified man walking around popular Istanbul square
Three other men remain in custody on similar charges
From Australia to Switzerland, the world welcomes 2017
Attacks persist despite army’s claim of clearing out Boko Haram
Carnage was retaliation for Turkey’s anti-terror efforts in Syria, Iraq
Stopgap measures by the European Union might not help in the long term
Last week’s attack in Berlin offers more evidence of ticking time bombs in the West
Police and the victim disagree on a possible motive behind the explosion
Justice Department wanted to designate Boko Haram a terror group in 2012
