The jihadis who used suicide bomb vests and high velocity AK-47s and Glock pistols to carry out their attack are understood to be from Russia, Uzbekistan and Kyrgyzstan.
All three are understood to have Russian passports in their possession.
The Turkish prime minister had previously linked the attack to ISIS – although the terror group is yet to claim any responsibility.
Sources have also revealed it’s feared a second cell is about to attack imminently.
The three men in Wednesday night’s attack are said to have hired a first floor apartment in the district of Fatih – 12 miles from the airport – 32 days ago and signed a one year contract.
An estate agent who rented the gang the property said they spoke in Russian and showed him Russian passports.
Neighbours have revealed the trio “spoke to no one” during their stay but were often heard arguing loudly.
Security officials believe the three men are part of a cell who trained with ISIS in Raqqa within the last year.
Investigators combing the apartment for evidence found the men had installed a metal door on the inside of their front door.
One of the men, dressed in a red T-shirt, has been named as Osman Vadinov, a Russian national.
Security officials are hunting a fourth member of the gang who is believed to be on the loose.
Police found notebooks and “manuals” near to the apartment which had been dumped by the gang.
The three men took a taxi to Istanbul’s Ataturk airport, the third largest in Europe, before engaging their bloody assault.
A taxi driver who picked them up told police the men were speaking Russian and were “calm and measured” and he “had no suspicions of them at all”.
A disturbing timeline has now emerged which reveals seven minutes of mayhem when the three jihadis split up to target different areas of the airport to create maximum damage and panic among travelers.
They arrived at 9.49pm local time (7.49pm BST), taking out their guns from a suitcase and with bombs in backpacks as well as suicide belts hidden underneath their jackets.
Two of the men went inside the airport while one made his way to the car park.
He was challenged by a security guard who became suspicious after seeing his large jacket.
After challenging him for identification the jihadi shot him and then detonated his explosives vest.
Read more at http://www.mirror.co.uk/news/world-news/chilling-picture-smiling-istanbul-airport-8315730#0DJHdICBE4mAs7hO.99