Just hours after writer Jamal Khashoggi was killed in the Saudi consulate in Istanbul, surveillance video showed a man strolling out of the diplomatic post apparently wearing the journalist’s clothes as part of a bid to sow confusion over his fate, according to reports.

The video broadcast by CNN followed reports from a pro-government Turkish newspaper that a member of Saudi Crown Prince Mohammed bin Salman’s entourage made four calls to the senior royal’s office from the consulate around the same time.

Meanwhile, Turkish crime scene investigators are focusing their inquiries on a garage in Istanbul where a Saudi consular vehicle had been parked.

Jamal Khashoggi and his fiancee
Jamal Khashoggi and his fiancee, Hatice Cengiz, at an apartment building in Istanbul, just hours before his death (A News via AP)

The revelations pile pressure on Saudi Arabia on the eve of Prince Mohammed’s high-profile investment summit in Riyadh, which has seen a raft of the world’s top business leaders decline to attend over the killing of The Washington Post writer.

Turkish president Recep Tayyip Erdogan has promised that details of Mr Khashoggi’s killing “will be revealed in all its nakedness” in an address he will make before parliament on Tuesday.

Omer Celik, a spokesman for Turkey’s ruling Justice and Development Party, said: “We are faced with a situation in which it was a brutally planned (killing) and efforts were made to cover it up.

“God willing, the results will be brought into the open, those responsible will be punished and no one will dare think of carrying out such a thing again.”

Saudi Arabia Investment Conference
Saudi employees print badges for participants of the Future Investment Initiative conference (AP)

The kingdom’s announcement on Saturday that Mr Khashoggi died in a “fistfight” prompted international scepticism and allegations of a cover-up to absolve the 33-year-old crown prince of direct responsibility.

Turkish media reports and officials maintain that a 15-member Saudi team flew to Istanbul on October 2, knowing Mr Khashoggi would enter the consulate to get a document he needed to get married.

Once he was inside, the Saudis accosted Mr Khashoggi, cut off his fingers, killed and dismembered the 59-year-old writer, according to Turkish media reports.

Surveillance video on CNN showed a man in Mr Khashoggi’s dress shirt, suit jacket and trousers, although he wore a different pair of shoes.

The consulate
Security personnel guard Saudi Arabia’s consulate in Istanbul (AP)

It cited a Turkish official as describing the man as a “body double” and a member of the Saudi team sent to Istanbul to target the writer.

The man then walks out of the consulate via its back exit with an accomplice, then takes a taxi to Istanbul’s famed Blue Mosque, where he goes to a public toilet, changes back out of the clothes and leaves.

He later eats dinner with his accomplice and goes back to a hotel, where footage shows him smiling and laughing.

The state-run broadcaster TRT also reported that a man who entered the consulate was seen leaving the building in Mr Khashoggi’s clothes.

In the days after Mr Khashoggi vanished, Saudi officials initially said he had left the consulate by its back door. Saudi Ambassador to the US Prince Khalid bin Salman, a brother of the crown prince, wrote on October 8 that Mr Khashoggi had left, and that claims the kingdom “have detained him or killed him are absolutely false, and baseless”.

Recep Tayyip Erdogan
Mr Erdogan has pledged to reveal more details of the killing (AP)

A separate report by the newspaper Yeni Safak said Maher Abdulaziz Mutreb, a member of Prince Mohammed’s entourage seen on trips to the US, France and Spain this year, made the calls from the consulate.

The newspaper said the four calls went to Bader al-Asaker, the head of Prince Mohammed’s office. It said another call went to the United States.

Pro-government newspapers have been leaking information about Mr Khashoggi’s killing, apparently with the help of Turkish security forces.

Yeni Safak reported last week that Saudi officials cut off Mr Khashoggi’s fingers and then decapitated him at the consulate as his fiancee waited outside.

Saudi Arabia so far has not acknowledged or explained Mr Mutreb’s presence in Istanbul or the presence of a forensics expert at the consulate before Mr Khashoggi arrived.

Jamal Khashoggi
Jamal Khashoggi enter is captured on CCTV entering the Saudi consulate (CCTV/TRT World via AP)

Last week, a leaked photo apparently taken from surveillance footage showed Mr Mutreb at the consulate, just ahead of Mr Khashoggi’s arrival.

Mr Mutreb’s name also matches that of a first secretary who once served as a diplomat at the Saudi Embassy in London, according to a 2007 list compiled by the UK Foreign Office.

By nightfall, Turkish police began searching an underground car parking garage in Istanbul’s Sultangazi district.

Surveillance footage on TRT showed what Turkish security officials described as suspicious actions, including an image of a man moving a bag from one vehicle to another.

Meanwhile, Saudi state media reported that both Prince Mohammed and King Salman have made calls to Mr Khashoggi’s son, Salah. Statements from the agency said both the king and the crown prince expressed their condolences over Mr Khashoggi’s death.

Five Turkish employees of the consulate have given testimony to prosecutors, Turkish media reported. Istanbul’s chief prosecutor had summoned 28 more staff members of the Saudi consulate, including Turkish citizens and foreign nationals, to give evidence.

Some Turkish employees reportedly said they were instructed not to go to work around the time that Mr Khashoggi disappeared.