The net is tightening on a man who previously traveled with Saudi Crown Prince Mohammed bin Salman to the US after a source told CNN he played a 'pivotal role' in 'the plot' to allegedly have Jamal Khashoggi killed.

After pro-government Turkish newspaper The Sabah published shots purporting to show Maher Abdulaziz Mutreb walking into the Saudi consulate building October 2 at 9.55am with several men trailing behind him on the day the writer vanished, a source suggests he was a mastermind behind a plan to kill him.

The CCTV images place him as one of the 15 people who allegedly tortured the Washington Post journalist before he disappeared in Istanbul, Turkey, after entering the same building at 1.14pm.

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CCTV images printed by the Sabah newspaper purportedly show royal protection officer Maher Abdulaziz Mutreb entering the Saudi Consulate in Istanbul at 9.55am on October 2, just hours before the journalist went missing

Another CCTV image claims to show Mutreb outside the Saudi consul general's residence later in the day at 16.53. CNN reports that a source claims he played a 'pivotal role' in the disappearance of the Washington Post journalist

Jamal Khashoggi (right) was also captured on CCTV arriving at the Saudi Arabian consulate in Istanbul. He has not been seen since and Turkey has accused Saudi agents of murdering him

Saudi Arabia's Crown Prince Mohammed bin Salman is said to be behind the alleged killing

Missing journalist Khashoggi, pictured in Switzerland in 2011, may have been murdered because he knew too much about the Saudi royal family, one of his friends has said

'He was seconded to an elite protection brigade within the Royal Guard to serve as the personal security force of [the crown prince],' the insider familiar with the Turkish investigation added about Mutreb's relationship with the Crown Prince.

He was the first secretary at the Saudi embassy in London and is reportedly described as a colonel in intelligence for the country.

The Sabah newspaper showed an image of the man at 4.53pm at the consul's home, then at 5.15pm checking out of a hotel. He later cleared airport security at 5.58pm.

Previously leaked surveillance footage showed consular vehicles moving from the consulate to the consul general's official residence, some 1.2 miles away, a little under two hours after Khashoggi walked inside.

Mutreb, reportedly now being sought by Turkish authorities for questioning over Khashoggi's disappearance, can be seen in the background as Crown Prince Mohammed bin Salman (right) visits a Habitat for Humanity in Houston, Texas in April

Sabah published pictures which it said showed Mutreb and others at Atatürk Airport at 5.58pm

According to Sabah, this CCTV image shows Mutreb 'and his people' with a large suitcase at a hotel in Turkey

A frame grab from a police CCTV video made available through Turkish Newspaper Sabah shows a private jet alleged to have ferried in a group of Saudi men suspected of being involved in Khashoggi's disappearance

Images shot by the Houston Chronicle and later distributed by the AP show the same man was in Prince Mohammed's entourage when he visited a Houston subdivision in April to see rebuilding efforts after Hurricane Harvey.

The same man wore lapel pins, including one of the flags of Saudi Arabia and America intertwined, that other bodyguards accompanying Prince Mohammed wore on the trip.

The three-week trip across the US saw Prince Mohammed meet with business leaders and celebrities, including Amazon billionaire Jeff Bezos, who now owns the Washington Post.

The Hill had previously reported Saudi Arabia's leaders were considering blaming a top Saudi intelligence officer for the apparent murder - according to the Hill.

The man who could be blamed for the killing, General Ahmed al-Assiri, is a top adviser to Salman.

CNN also reported sources familiar with the case claimed that the alleged mission that resulted in the journalist's disappearance was organized by a high-ranking officer with Saudi Arabia's main intelligence service - the General Intelligence Presidency.

CNN reported one of the sources as saying that the officer was close to the inner circle of the powerful Crown Prince and that the officer assembled and sent his own team to interrogate Khashoggi suspecting him of having ties to Qatar - the kingdom's arch rival. CNN reported that there had been no evidence to substantiate such a link.

Meshal Saad M. Albostani (left), one of the 15 Saudis who flew to Turkey on the day journalist Khashoggi (right), disappeared has been killed in a car crash, it has been claimed

Investigators are said to have collected CCTV images from the entrance to Belgrad Forest to the north of the city amid fears the US-based Saudi writer's body was dumped there

Turkish police are searching Belgrad Forest (pictured) outside Istanbul in the hunt for missing journalist Khashoggi, according to local reports

Turkish police have been searching an area of woodland outside Istanbul as well as a farm house across the Marmara Sea, in the hunt for the missing journalist, according to local reports.

Investigators are said to have collected CCTV images from the entrance to Belgrad Forest to the north of the city amid fears the US-based Saudi writer's body was dumped there.

After tracing the route of the convoy of cars which left the Saudi consulate on the day the journalist went missing, the search moved to woodland near the city of Yalova, a 90-kilometre (55 mile) drive south of Istanbul.

They are reportedly also preparing to 'excavate' a villa in Yalova province, where one of the vehicles linked to the Saudi 'hit squad' was seen, according to Turkish media.

NT's report of the forest search comes after it was claimed that one of the 15 Saudis who flew to Turkey on the day Khashoggi disappeared had been killed in a 'suspicious' car crash. Meshal Saad M. Albostani, a lieutenant of the Saudi Royal Air Force, is said to have died in the capital Riyadh.

Politicians, tycoons and CEOs pull out of Saudi investment conference Three European government ministers have joined an array of corporate chiefs in pulling out of an upcoming investment conference in Saudi Arabia, following the disappearance of Saudi journalist Jamal Khashoggi. Company leaders risk losing lucrative business with the kingdom by shunning the conference, and countries such as the United States, Britain and France have several defence deals at stake. But Turkish claims - denied by Riyadh - that Khashoggi was killed by a hit squad in the Saudi consulate in Istanbul on October 2 have put them in an awkward spot. International Monetary Fund chief Christine Lagarde has already withdrawn from the Future Investment Initiative taking place on October 23-25 in Riyadh, which is billed as a showcase for the economic reforms of Crown Prince Mohammed bin Salman. US Treasury Secretary Steven Mnuchin said he would decide later on Thursday whether to attend, after reviewing the outcome of a diplomatic dash by Secretary of State Mike Pompeo to Saudi Arabia and Turkey. The conference's website previously featured a star-studded list of speakers. But that has been removed amid the steady flow of defections. Here is a list of no-shows: POLITICS - French Economy Minister Bruno Le Maire - British International Trade Secretary Liam Fox - Dutch Finance Minister Wopke Hoekstra FINANCE - HSBC chief executive John Flint - Credit Suisse CEO Tidjane Thiam - MasterCard CEO Ajay Banga (HSBC, Credit Suisse and MasterCard are listed among the eight 'strategic partners' of the conference. Another is Siemens, whose boss Joe Kaeser says he is still mulling whether to come.) - BNP Paribas chairman Jean Lemierre - Societe Generale CEO Frederic Oudea - JPMorgan Chase CEO Jamie Dimon - BlackRock chief Larry Fink - Blackstone CEO Stephen Schwarzman - Standard Chartered CEO Bill Winters - London Stock Exchange CEO David Schwimmer INDUSTRY/TECHNOLOGY - Ford chairman Bill Ford - Uber CEO Dara Khosrowshahi - British billionaire Richard Branson - Thrive CEO Ariana Huffington - Google Cloud CEO Diane Greene MEDIA - Viacom CEO Bob Bakish. In addition, multiple media groups have withdrawn executives or journalists who were due to take part in the conference, including CNN, Bloomberg, The Economist, The New York Times, CNBC and the Financial Times. Advertisement

Pro-government newspaper Yeni Safak reported that there was little more detail about the car crash that supposedly left Albostani dead. It's the same publication that reported there were audio recordings documenting the alleged interrogation and torture of Khashoggi.

But Turkey has yet to share with the US government or key European allies any graphic audio or video evidence it allegedly collected on the US-based Saudi journalist's visit to the embassy.

Last week, Turkish newspaper Sabah released CCTV images of Albostani among a group of men who flew into Istanbul on the day Khashoggi went missing. They were pictured arriving at Ataturk airport's border control having flown into Turkey in two private jets from the Saudi capital Riyadh.

Turkish officials also provided CNN with passport scans taken October 2 of seven other men in connection with the team.

One of them seems to belong to Salah Muhammad al-Tubaiqi (Salah Mohammed A Tubaigy in the document) - head of forensic medicine at the Saudi Ministry of Interior.

Another is reportedly Muhammad Saad al-Zahrani, who has appeared on Saudi state TV with the crown prince.

Meanwhile, a Saudi team investigating the disappearance has left the Saudi consul general's residence in Istanbul, after a nine-hour search a Reuters witness said early on Thursday.

Turkish investigators had also searched the Saudi consulate for some nine hours on Monday as part of the investigation.

Two weeks after the disappearance, the United States and allies have collected some intelligence through their own sources and methods, which partly confirms news reports based on leaks of audio recordings, four sources told Reuters.

Yeni Safak had reported that Khashoggi's alleged torturers severed Khashoggi's fingers during an interrogation, and that he was killed within minutes. According to the report, his body was later beheaded and dismembered by his killers.

A New York Times report on Wednesday cited a senior Turkish official confirming the details published by Yeni Safak. Two Turkish government officials contacted by Reuters declined to confirm the report.

The reluctance of the Turks to turn over hard evidence they have said they have documenting Khashoggi's fate has led US and European security officials to assess that the most brutal accounts of Khashoggi's demise are likely accurate, the sources said.

US President Donald Trump appeared to confirm the lack of evidence in US hands when he said on Wednesday that the United States had asked Turkey for any audio or video evidence it may have related to Khashoggi.

'We have asked for it, if it exists ... I'm not sure yet that it exists, probably does, possibly does,' Trump said.

'I'll have a full report on that from Mike (Pompeo) when he comes back ... That's going to be the first question I ask,' he said.

Khashoggi, a prominent critic of Saudi policies and columnist for the Washington Post who was living in the United States, vanished after entering the Saudi consulate in Istanbul to get marriage documents.

Secretary of State Pompeo refused to blame Saudi Arabia for the alleged killing of Khashoggi after his visit to Turkey for talks with President Recep Erdogan.

Pompeo headed straight to the Turkish capital, Ankara, after visiting Saudi Arabia to discuss the progress of the investigation into the writer's alleged killing.

He said after meeting the Saudi royal family that officials in the kingdom told him their investigation into the disappearance and alleged killing won't spare anyone, including royals.

Thursday afternoon, Russia's President Vladimir Putin said the Kremlin will wait for the outcome of a probe into the disappearance of the dissident writer before deciding what impact it may have on relations with Saudi Arabia.

Speaking at an international policy forum, Putin said 'those who believe that there was a murder must present evidence.'

He noted that 'the disappearance was a tragedy, but we need to understand what happened' before deciding what impact it may have on Russia's relations with Saudi Arabia.

Putin noted that 'the US bears a certain responsibility' for what happened to Khashoggi, who went into self-imposed exile in the US.