Istanbul(CNN) A member of the 15-man team suspected in the death of Jamal Khashoggi dressed up in his clothes and was captured on surveillance cameras around Istanbul on the day the journalist was killed, a senior Turkish official has told CNN.

CNN has obtained exclusive law enforcement surveillance footage, part of the Turkish government's investigation, that appears to show the man leaving the Saudi consulate by the back door, wearing Khashoggi's clothes, a fake beard, and glasses.

The same man was seen in Khashoggi's clothing, according to the Turkish case, at the city's world-famous Blue Mosque just hours after the journalist was last seen alive entering the consulate on October 2.

The man in the video, identified by the official as Mustafa al-Madani, was allegedly part of what investigators have said was a hit squad, sent to kill the journalist during a scheduled appointment to get papers for his upcoming wedding.

Madani at the Blue Mosque in Istanbul captured on law enforcement surveillance footage, according to a Turkish official.

Saudi Arabia has presented a shifting narrative of what happened to Khashoggi. After weeks of denying involvement in Khashoggi's disappearance, Saudi Arabia said that he was killed in the Istanbul consulate, saying his death was the result of a "fistfight." A Saudi source close to the royal palace later told CNN that the Washington Post journalist died in a chokehold. On Sunday, its foreign minister, Adel al-Jubeir, went further, describing Khashoggi's death on Fox News as a "murder" and a "tremendous mistake." He also said they "don't know where the body is."

"We are determined to uncover every stone. We are determined to find out all the facts. And we are determined to punish those who are responsible for this murder," he said in the interview.

In the apparent cover-up that followed Khashoggi's death, Madani, 57, who is of similar height, age and build to Khashoggi, 59, was used as a decoy for the journalist, according to the Turkish official.

A senior Turkish official told CNN that the video showed that Madani was brought to Istanbul to act as a body double.

"You don't need a body double for a rendition or an interrogation," the official said. "Our assessment has not changed since October 6. This was a premeditated murder and the body was moved out of the consulate."

A Saudi source would not confirm or deny that Madani was sent to act as a body double, though he emphasized that the killing of Khashoggi was not intentional.

Madani, a decade older than the other members of the 15-man team, exited the consulate building by the back door along with an alleged accomplice. Madani was wearing what the video appears to show to be Khashoggi's dark blazer, gray shirt opened at the collar and trousers.

Four hours earlier Madani had entered the consulate by the front door, alongside an alleged accomplice. Saudi's forensic medicine chief Salah al-Tubaiqi, another key suspect who was identified using facial recognition analysis together with CNN's timeline of events that day, was also present. The video appears to show Madani without a beard, wearing a blue and white checked shirt and dark blue trousers. When he exited the consulate dressed as Khashoggi, the video then appears to show him wearing the same dark pair of sneakers with white soles that he first arrived in prior to the journalist's death.

"Khashoggi's clothes were probably still warm when Madani put them on," the senior Turkish official told CNN.

The journalist's fiancee Hatice Cengiz, who was waiting outside the consulate's front entrance and raised the alarm when he didn't return, was told by a consulate guard that he may have exited the building through the back door, Khashoggi's friend Turan Kislakci told CNN.

This surveillance footage is another piece of evidence in the mysterious case of what happened to Khashoggi after he entered the consulate almost three weeks ago. It forms part of the wider investigation by Turkish officials into the events of that day and the continued interrogation and international questioning of Saudi Arabia's version of how the journalist died.

Turkish officials have been leaking a steady drip feed of details from the investigation to journalists but they have yet to release a key audio recording which sources say exists from inside the Saudi consulate. Turkey has not publicly admitted the existence of the audio.

Timeline

Below are Madani and his accomplice's movements and actions, according to the video footage obtained by CNN and a senior Turkish official, on the day Khashoggi was killed: