There was something of Hannibal Lecter in the gruesome murder of outspoken journalist Jamal Khashoggi in the Saudi Arabian embassy in Istanbul — minus, one hopes, the cannibalism.

He was suffocated (bag over his head), throttled, fingers snipped off (probably while still alive), head and limbs hacked away by a forensic doctor wielding a bone saw (possibly while still alive), his corpse quartered then sliced into 15 pieces.

Having stepped inside the embassy on October 2 last year, he could have been quietly disposed of, a single bullet to the head or injected with some lethal drug by the hit squad sent from Riyadh to deal with him.

Even more explosively, there is a suggestion one particularly hot secret might have involved one of the world’s most controversial and unpredictable leaders — Donald Trump. President Trump is pictured with Saudi Arabia's Crown Prince Mohammed bin Salman

Instead, in an overkill of gore, he was butchered, presumably as an example to others and so someone, somewhere, could savour the details. His disappearance, followed by a cover-up then the drip-drip of inside information revealing the grisly details of how he died, provoked international revulsion and turmoil.

All suspicion pointed at Mohammed bin Salman, known by his initials as MbS, the newish Crown Prince (and effective day-to-day ruler) of Saudi Arabia, as the instigator.

Five months on, they still do — despite the 33-year-old prince’s denial that he had anything to do with the killing and his insistence that some of his henchmen must have gone rogue and carried it out without his knowledge.

But what has puzzled observers since the story broke was what Khashoggi had done to merit such extreme, almost medieval, retribution. He was certainly a thorn in the side of the Saudi monarchy with his criticisms.

Following a ban from public speaking imposed a year earlier, he left the kingdom for the U.S. and continued his attacks on the Crown Prince’s policies in the scathing columns he wrote each month in the Washington Post newspaper.

Having stepped inside the embassy on October 2 last year, above, he could have been quietly disposed of, a single bullet to the head or injected with some lethal drug by the hit squad sent from Riyadh to deal with him. Instead, in an overkill of gore, he was butchered, presumably as an example to others and so someone, somewhere, could savour the details

His very last one spoke of ‘poverty, mismanagement and poor education’ in his homeland and demanded freedom of expression rather than what he termed ‘the Middle East’s version of an Iron Curtain spreading hate through propaganda’.

He refused to be impressed by so-called ‘modernisation’ programmes introduced with great fanfare by the Crown Prince — such as allowing women to drive and establishing a Red Sea resort where bikinis could be worn — because they came with a ruthless clampdown on anyone who dared to disagree with him.

The prince tried to woo him back by offering a place at his side as an adviser, but Khashoggi rejected the advance. In a broadcast on the BBC he declared his opposition to the prince: ‘One-man rule is always bad, in any country.’

But a new book on his murder hints that there was more to his death than the simple gagging of a persistent critic, albeit an influential one who was heralded as the most famous political pundit in the Arab world, with close to two million followers on Twitter.

For decades, says its author Owen Wilson, Khashoggi had been a golden boy, he and his family embedded among the power brokers in Saudi Arabia.

His grandfather had been personal physician to King Ibn Saud, the founder of the nation, and he himself was a trusted asset of Saudi intelligence when he worked as a foreign correspondent in such places as Afghanistan and interviewed Osama Bin Laden.

For many years, journalist Jamal Khashoggi had been a favoured insider. So when he quit the kingdom and took up residence in the U.S. in the summer of 2017, it was viewed in some quarters as a defection

He had been privy to many Saudi secrets as a confidant of Prince Turki al-Faisal, Saudi Arabia’s long-standing intelligence chief, and had also been his adviser when he was Saudi ambassador to first London then Washington.

All this raises the question of whether Khashoggi knew too much. Was he party to some damaging secret that his one-time friends in Riyadh feared he might spill unless silenced?

Even more explosively, there is a suggestion one particularly hot secret might have involved one of the world’s most controversial and unpredictable leaders — Donald Trump.

To Wilson it is highly significant that what caused the Saudi authorities to ban Khashoggi from publishing or appearing on TV there, thus prompting him to flee to America, was not what he was saying about the Crown Prince but because he was critical of Trump shortly after his election victory in 2016.

‘The Saudi government,’ writes Wilson, ‘presumably saw the vain and volatile billionaire and soon-to-be president as their mark and feared Khashoggi’s views might be seen as those among the royal elite.

Khashoggi, 59, had fallen in love with 36-year-old Hatice Cengiz, above, a Turkish PhD student at university in Istanbul. They planned to marry and live in Turkey — whose president Tayyip Erdogan is an arch-rival of Saudi Arabia in the power politics of the Middle East [File photo]

Stung, Saudi Arabia not only forbade him from public speaking, it also issued an official Press release to distance itself from him.’ He concludes: ‘What he knew about Trump was so sensitive that his credibility had to be undermined at all cost.’

That Khashoggi then chose to write for the Washington Post — an avid opponent of Trump — was a particular concern. What bombshell was he going to drop next in his column?

The Saudis knew, says Wilson, that the once highly-placed Khashoggi had an insight into the kingdom’s long-held desire to develop a nuclear capability, as a counterweight to the nuclear bomb ambitions of Iran, its number one enemy.

He might also have been aware of Trump’s keenness to sell nuclear technology to them. Such knowledge, he suggests, made Khashoggi a liability to the Saudis ‘that could only be cancelled by eliminating him’.

Such a scenario may appear far-fetched — surely it’s not in America’s interest to provide nuclear know-how of any sort to the volatile Middle East region? Yet coincidentally, very recent events now show that this is something under active consideration.

Last month, Washington was agog when a congressional inquiry revealed that what are described as ‘senior White House officials and Trump’s close relatives and business cronies’ have been secretly pushing a plan to transfer sensitive U.S. nuclear technology to Riyadh.

Jared Kushner, Trump’s son-in-law and Middle East envoy, is said to be one of those closely involved.

A report in mid-February by the House Oversight and Reform Committee, apparently based on internal White House documents and the accounts of whistle-blowers, claimed that secret talks had indeed been going on. It said that any deal would be in violation of U.S. non-proliferation laws.

Although the discussions concerned non-military use — the building of nuclear power plants — the committee feared the technology could be the pathway to nuclear weapons.

It also pointed up a possible conflict of interest for those ‘pressing aggressively to bypass controls’ and said it planned to urgently expand its inquiry ‘to determine whether the actions being pursued by the Trump administration are in the national security interests of the U.S. or, rather, serve those who stand to gain financially’.

Private commercial interests, it suggested, ‘stand to reap billions of dollars’.

Trump’s horrified opponents raised the question of whether an impending nuclear deal with the Saudis was one reason the president was slow to react to Khashoggi’s murder and notably more reluctant than other world leaders to take tough action against Saudi Arabia.

It is equally possible the Saudis believed Khashoggi had wind of these sensitive discussions, feared he might reveal them in his column and took action to shut him up before he could.

Here, possibly, was the final nail in his coffin, leading the Crown Prince and his cronies to see the exiled writer and commentator as a threat so potent they needed to get rid of him.

For many years, he had been a favoured insider. So when he quit the kingdom and took up residence in the U.S. in the summer of 2017, it was viewed in some quarters as a defection. Here was an important player who possessed sensitive information that would be disastrous if it fell into the wrong hands.

Trump’s horrified opponents raised the question of whether an impending nuclear deal with the Saudis was one reason the president was slow to react to Khashoggi’s murder and notably more reluctant than other world leaders to take tough action against Saudi Arabia

He now became a pariah, not just an opponent whose views contradicted those of the prince but a ‘traitor’ — the word that recordings reveal was hurled at him by one of his attackers as they were cutting him to pieces. His intended marriage — it would have been his fourth — had added fuel to the firestorm building up against him.

Khashoggi, 59, had fallen in love with 36-year-old Hatice Cengiz, a Turkish PhD student at university in Istanbul. They planned to marry and live in Turkey — whose president Tayyip Erdogan is an arch-rival of Saudi Arabia in the power politics of the Middle East.

This was another cause of paranoia in Riyadh. Was Khashoggi, with all his insider’s knowledge of the workings of the kingdom, about to throw in his lot with a potential enemy?

That impending marriage was his downfall in another sense, too — it made it easier to lure him to his death.

For the Saudis to assassinate him on American soil would have been diplomatic madness. And since there was no way he was going to risk a visit to Saudi, it had to be on neutral soil.

They couple’s plan was to marry on Khashoggi’s 60th birthday on October 13, but first he needed copies of his divorce papers. He tried to obtain them at the Saudi embassy in Washington but the ambassador there — Prince Khalid, the Crown Prince’s brother — told him he would have to go to Istanbul (where the wedding was to be) to get them.

He was assured he would be safe. Khashoggi was no fool. He realised he would not be welcome but told a pal: ‘I’m not afraid. The most they can do is interrogate me. And I can give them answers. I’ve nothing to hide.’

But he was clearly nervous something untoward might happen and made sure his fiancee accompanied him to the embassy. She waited outside as he went through the door — a scene that would be captured by surveillance cameras and later flashed around the world as the last sighting of him.

He left her his mobile and told her that if he did not come out after an hour, she should phone a high-level contact in Istanbul, an adviser to President Erdogan.

Inside, he was shown to the office of the consul-general, and was sitting there when members of the 15-man hit squad dispatched from Riyadh came in.

He knew some of them, including their leader, Major-General Maher Mutreb, attached to the Crown Prince’s security detail, and Dr Salah al-Tubaigy, head of forensics at the Saudi interior ministry.

Saudi Crown Prince Mohammed bin Salman, left, is pictured with his father King Salman. The Saudis wanted to silence Khashoggi when he was alive, but dead, he shouted the evils of the kingdom to the world like never before [File photo]

They told him he had to return to Saudi and if he refused he would be kidnapped and taken there by force. When he resisted, shouting at them to ‘release my arm!’, they embarked on a seven-minute orgy of extreme violence.

At some point a Skype call was apparently made to one of the Crown Prince’s closest advisers in Riyadh. This adviser, Saud al-Qahtani, hurled insults at Khashoggi who returned them in kind. Qahtani then ordered the men to: ‘Bring me the head of the dog!’ And that is what they did.

All this happened behind closed doors. It seems the consulate’s local staff had unexpectedly been given the afternoon off and the internal CCTV wasn’t on.

And the killers might have got away with it. These thugs, says Wilson, were experts at the ‘disappearing’ of people. But they cannot have reckoned on his girlfriend being outside, and when after several hours he failed to re-emerge, she alerted the authorities.

The story was about to explode into a global scandal. The Saudis wanted to silence Khashoggi when he was alive, but dead, he shouted the evils of the kingdom to the world like never before.

Bit by bit, leaked information about the macabre events inside the embassy gave the lie to Saudi denials that they had killed him. An audio tape mysteriously surfaced of the actual torture and murder, probably, says Wilson, from Russian intelligence sources who had the embassy bugged.

Then, the story contorted to protect the Crown Prince, with the blame being placed on rogue elements among his entourage — improbable as that sounds given that, like Putin in Russia, his grip on Saudi Arabia is such that little goes on without his approval.

There were high-level sackings among his staff and it was announced that 18 men — all soldiers and intelligence operatives — were under arrest and would be tried in Saudi courts for killing Khashoggi. The death sentence is being sought against five of them and no doubt one day those who know too much about the Crown Prince’s involvement will pay with their heads in Riyadh’s grimly named Chop Square.

But the story is unlikely to go away even then. There are too many unanswered questions.

What happened to Khashoggi’s remains? It seems likely that some of them at least — the head, the fingers? — were bundled into diplomatic bags and flown to Saudi Arabia in private jets that left Istanbul airport just hours after he disappeared.

All suspicion pointed at Mohammed bin Salman, known by his initials as MbS, the newish Crown Prince (and effective day-to-day ruler) of Saudi Arabia, as the instigator. Five months on, they still do — despite the 33-year-old prince’s denial that he had anything to do with the killing [File photo]

If the rest of him was buried in Turkey, the grave has not been found. However, according to one investigation, his body was burned in a specially-constructed tandoori oven installed in the garden of the consul-general’s home just yards from the Saudi consulate.

The Arabic TV channel Al Jazeera interviewed a worker who claimed he constructed the furnace according to specifications from the Saudi consul. It had to be deep and withstand temperatures above 1,000 degrees Celsius — hot enough to melt metal.

Large quantities of barbecue meat were grilled in the oven after the killing in order to cover up the cremation of the Saudi writer’s body, Turkish authorities reported, adding that the process took place over a period of three days.

According to Wilson, suspicious neighbours reported that for the first time ever there had been a barbecue beside the pool in the large fenced-in garden.

Then there is the question of how much intelligence sources in the U.S. knew in advance. Wilson cites claims that they intercepted Saudi communications and discovered action was being planned against Khashoggi, yet failed to warn him, despite him being at that point a resident of the U.S.

Now there is the latest twist with the possible (and dodgy) involvement of those close to the Trump camp trying to swing a nuclear deal with Saudi Arabia.

There are clearly high stakes involved — with power games being played out on all sides, from Riyadh to Washington and Moscow to Istanbul and beyond.

The Khashoggi affair is not over. It is one that, like the man himself as he desperately struggled for his life in the Istanbul embassy, we can be sure will not easily die.

Owen Wilson is a pseudonym for an author who, for security reasons, has chosen not to use his real name.

Khashoggi and The Crown Prince: The Secret Files by Owen Wilson will be published by Gibson Square on March 14 at £8.99. ©Owen Wilson.

To buy a copy for £7.19 (20 per cent discount) go to mailshop.co.uk/books or call 0844 571 0640. Offer valid until 20/03/19, p&p is free on orders over £15.