Funerals of many of the victims - which included foreign nationals - have been taking place
The suspect in the Istanbul nightclub attack appears to be well versed in guerrilla warfare and may have trained in Syria, reports said, as new footage shows him in the Turkish city of Konya before the New Year’s Eve rampage.
As the suspect remains at large, some of the 39 victims of the attack on the Reina club were laid to rest on Tuesday.
Turkish authorities say they have now established the identity of the attacker but have not released any further details.
It comes as Turkish police detained five Islamic State suspects in the western city of Izmir in an ongoing operation, the state-run Anadolu agency said on Wednesday.
The attacker shot dead a police officer and a civilian at the entrance of the club, then opened fire with an automatic rifle inside. He reloaded his weapon half a dozen times and shot the wounded as they lay on the ground.
A security source in the country told the Reuters news agency that the "assailant has experience in combat for sure.
"He could have been fighting in Syria for years," the source reportedly added.
The Islamic State has claimed responsibility for the attack, which also wounded nearly 70 people, and the security source said he was likely to have been directed in his actions by the jihadist group.
The gunman has been seen in a number of videos since the massacre, including taking selfie footage as he silently toured one of Istanbul's most famous spots, Taksim Square.
In the latest CCTV footage, obtained by the Turkish news agency DHA, he is seen walking at a bus terminal in the central city of Konya last month.
According to the Turkish newspaper Haberturk, the alleged gunman entered Turkey from Syria, going into Konya in November and travelling with his wife and two children so as not to attract attention.
The family rented a studio in Konya, paying three months of rent in advance, reports said. He told the real estate agent he was looking for work, according to the reports.
The man's wife was arrested in Konya on Tuesday and, according to newspaper Hurriyet, she told police she learned about the attack on TV and did not know her husband harboured "sympathies" towards Islamic State.
Neither she nor her husband has been identified. But the deputy prime minister, Numan Kurtulmus, said authorities are close to identifying the gunman after finding his fingerprints.
Many of the victims in the glamorous and popular nightclub were foreigners.
In Lebanon, which lost three nationals, hundreds of people attended the funerals.
One of the victims, 26-year-old fitness instructor Elias Wardini, was recently engaged to be married. His family and friends set off fireworks as his white coffin arrived at a church in Beirut.
In the Israeli city of Tira, thousands attended the funeral of Layan Nasser, an 18-year-old Arab Israeli dental assistant.