Turkish media on Tuesday ran a "selfie video" of a man they say is the gunman who killed 39 people, most of them foreigners, at an Istanbul nightclub. The video broadcast on Turkish television shows the alleged gunman filming himself with a cell phone at Istanbul's Taksim square. It wasn't immediately clear if it was filmed before or after the New Year's massacre at the Reina nightclub. No details have been released as to why the authorities might think the man on the video is a suspect in New Year's attack, or how the footage was obtained. The ISIS group claimed the attack on Monday, saying a "soldier of the caliphate" had carried out the mass shooting in response to Turkish military operations against IS in northern Syria. The authorities said they were making progress in identifying the gunman, who is still at large, and that at least eight people have been detained in connection with the attack. There were conflicting reports over the gunman's identity. Several media outlets on Monday, citing unnamed security sources, said the man was believed to be from a Central Asian nation and may have been part of the same cell that staged a June attack on Istanbul's Ataturk Airport that killed 45 people. Haber Turk newspaper on Tuesday said the man is thought to be a member of China's Muslim Uighur minority. Without citing a source, the newspaper said he had arrived in the Turkish city of Konya with his wife and two children in order not to raise suspicions. His family members were detained, the newspaper said.