The gunman who opened fire and killed 39 people in an Istanbul nightclub early New Year's Day has been identified, police said. Turkish Foreign Minister Mevlut Çavusoglu announced the news but did not give a name of the suspect or his nationality. Turkish authorities also identified and detained five alleged ISIS suspects in connection with the attack. At least 21 people are already detained, who authorities believe helped carry out the attack at Reina nightclub.