The possibility that acid was used to dissolve the body of missing Saudi journalist Jamal Khashoggi is one line of inquiry, a well-placed source has told Sky News.

Sky's special correspondent Alex Crawford, in Istanbul, said she was told by someone "very close to the inquiry" that one of the theories is Mr Khashoggi's remains were destroyed in a "very fast-acting chemical acid".

It comes as details emerge of an apparent audio recording of the alleged torture and murder of the Washington Post columnist in the Saudi consulate in the Turkish city.

Donald Trump said on Wednesday the US has asked for the audio "if it exists", as he called Saudi Arabia an important ally while noting it is an integral customer for US military exports.

The US president also denied covering up for his ally, saying: "No not at all, I just want to find out what's happening"


"I'm not giving cover at all."

Image: Turkish police officers and a sniffer dog examine the outside of the Saudi consul's home in Istanbul

The journalist's body was reportedly disposed of at the nearby official residence of Saudi consul Mohammed al-Otaibi.

Mr Khashoggi, a Saudi dissident and US resident, has been missing since 2 October when he visited the Saudi consulate to obtain documents he needed to get married. He was reportedly killed soon after entering the building.

Image: Turkish forensic officers at the Saudi consul's house in Istanbul

Image: Turkish forensics experts left the Saudi consul general's house early on Thursday morning

Crawford said a "very well-placed" source told her the audio recording included a conversation between Mr al-Otaibi and Mr Khashoggi, after which there was "a beating".

The source said the recording later revealed the journalist, who has been a critic of the regime, was "drugged" and "killed", before a Saudi forensics expert told others to put in headphones and listen to music while he took seven minutes to dismember the body.

Turkish media reported a 15-member Saudi "assassination squad" confronted the writer at the consulate and his screams could be heard throughout the building.

Yeni Safak, a strongly pro-government newspaper, said Mr al-Otaibi could be heard telling those allegedly torturing Mr Khashoggi: "Do this outside; you're going to get me in trouble."

The newspaper said one of the Saudi "torturers" replied: "Shut up if you want to live when you return to (Saudi) Arabia."

The recording also revealed Mr Khashoggi had fingers cut off and was told to "shut up" or face being killed, Yeni Safak reported.

Image: Mr Khashoggi went missing after entering the Saudi consulate on 2 October

Image: Forensics officers searching the Saudi consul's backyard

On Wednesday afternoon, Turkish police went into the nearby Saudi consul's official residence after protracted negotiations with Riyadh over the terms of a search.

Around a dozen forensics officers carrying extensive equipment, went in to the building, where they also searched the garden, Crawford said.

After an overnight search they were seen leaving the large house at about 5am on Thursday with bags of evidence.

Mr al-Otaibi, reportedly left Turkey on Tuesday after it was announced the property would be searched in connection with the journalist's disappearance.

Turkish police had earlier spent more than eight hours searching the consulate building, taking away soil and DNA samples for further examination.

Image: Saudi consul Mohammad al-Otaibi has reportedly left Turkey

A steady drip of leaks from police, diplomatic and intelligence sources have claimed that the 60-year-old was murdered for his opposition to the Saudi regime, allegations the Gulf kingdom has called "baseless".

Other reports suggest Saudi Arabia may admit he died during a botched interrogation.

Another Turkish newspaper, Sabah, has published the names and CCTV pictures of the 15 men who allegedly made a one-day trip to Istanbul on the day Mr Khashoggi disappeared.

One of the men appears to be bodyguard Maher Abdulaziz Mutreb, a regular member of Crown Prince Mohammed bin Salman's entourage.

Another pictured is reportedly forensic expert Dr Salah Muhammed al Tubaigy.

Image: Maher Abdulaziz Mutreb arriving in Spain with Crown Prince Mohammed bin Salman

Image: Forensics expert Dr Salah Muhammed al Tubaigy

US secretary of state Mike Pompeo met King Salman and Crown Prince Mohammed bin Salman in Riyadh on Wednesday.

Mr Pompeo told reporters that the regime "made a commitment to hold anyone connected to any wrongdoing that may be found accountable for that, whether they are a senior officer or official."

A report by the Reuters news agency quoting Saudi media reports saying the Saudi consul-general had been sacked and was under investigation was later withdrawn.

The US president says he is waiting for his secretary of state to return before making any judgement.

In an interview on Wednesday, Mr Trump said he did not want to walk away from Saudi Arabia over the issue as the US relies on the kingdom in the fight against terrorism.

He said: "You know we need Saudi Arabia in terms of our fight against all of the terrorism, everything that's happening in Iran and other places."