Footages have revealed that Saudi team scouted in Istanbul's Belgrad Forest before the murder of Saudi journalist Jamal Khashoggi, according to security sources on Wednesday.

As part of the probe launched by the Chief Public Prosecutors' Office in Istanbul, a special security team went through 2,000-hour-long footages from a total of 137 surveillance cameras at 62 points.

The team found that on Oct.1, the Saudi team scouted the forest with a diplomatic vehicle that belonged to the consulate, while another photograph showed Khashoggi's arrival to Ataturk Airport on the same day.

The comprehensive investigation on surveillance cameras around the Saudi Consulate and in several areas of Istanbul -- including Levent and Sultanahmet -- reveals clues for the killing of Khashoggi step by step.

The footages show activities of the 15 Saudis -- who arrived in Istanbul on two planes to kill Khashoggi and visited the consulate while he was still inside -- and the consulate officials.

One of the surveillance footages shows Saudis' activities just a day before the murder, where the consulate officials are seen at an attempt to enter their consulate through its garden gate with a diplomatic vehicle.

In addition, three Saudi officials were spotted arriving in Istanbul on a plane and staying at a hotel before visiting the consulate.

Khashoggi, a columnist for The Washington Post, had gone missing since entering the Saudi Consulate in Istanbul on Oct. 2.

After days of denying to know his whereabouts, Saudi Arabia last week claimed Khashoggi died during a fight inside the consulate.

Saudi King Salman bin Abdulaziz sacked the deputy of the intelligence service and a top aide and ordered the arrest of 18 suspects over the case.