The unnamed attacker is understood to be from either East Turkestan, Afghanistan or Chechnya, but his exact nationality is still unknown.
Turkish intelligence belueves he may be a member of the East Turkestan branch of ISIS.
The mystery man is still on the run after ruthlessly gunning down 39 revellers who were celebrating the New Year at one of the country’s most exclusive night spots.
A further 69 people were wounded in the attack and it is possible the death toll may rise.
A major manhunt is underway but has yet to bring the man to justice.
CCTV images show the attacker firing an opening salvo of shots from outside the club before gaining entry and going on the rampage.
He reportedly shouted “Allahu Akbar” as he mercilessly executed dozens of party goers with his kalashnikov.
The terrorist managed to escape the scene, leaving his gun inside the nightclub, and “taking advantage of the chaos” in order to flee.
Fifteen of the dead are believed to be foreign nationals, including one Israeli woman and people from Saudi Arabia, Morocco, Lebanon and Libya.
Turkey’s president Tayyip Erdogan vowed to fight against attacks by terror groups and their backers.
He said: “As a nation, we will fight to the end against not just the armed attacks of terror groups and the forces behind them, but also against their economic, political and social attacks.
“They are trying to create chaos, demoralize our people, and destabilize our country with abominable attacks which target civilians.
“We will retain our cool-headedness as a nation, standing more closely together, and we will never give ground to such dirty games.”