US intelligence officials think the Saudi Crown Prince Mohammed bin Salman ordered the killing of journalist Jamal Khashoggi, according to a US official.
The claim, first reported by The Washington Post, has been denied by the Saudi government.
It is thought that the conclusion has been drawn following a detailed assessment of the evidence and is based on the idea that such an operation would need approval from the Crown Prince.
Mr Khashoggi, a Saudi who lived in the United States, was killed on October 2 at the Saudi Consulate in Istanbul.
The Washington Post columnist was often critical of the royal family and Turkish and Saudi authorities say he was killed inside the consulate by a team from the kingdom after he went there to get marriage documents.
The conclusion by US intelligence officials comes as Trump administration sanctioned 17 Saudi officials for their alleged role in the killing, including Mohammed al-Otaibi, the diplomat in charge of the consulate, and Maher Mutreb, who was part of the crown prince’s entourage on trips abroad.
The sanctions freeze any assets the 17 may have in the US and prohibit any Americans from doing business with them.
But politicians have called on the administration to curtail arms sales to Saudi Arabia or take other harsher punitive measures.
Donald Trump called the killing “one of the worst cover-ups in the history of cover-ups” but has resisted calls to cut off arms sales to the kingdom.
The top prosecutor in Saudi Arabia announced he will seek the death penalty against five men suspected in the killing.
The Washington Post, citing unnamed sources, also reported that US intelligence agencies have reviewed a phone call between Mr Khashoggi and the prince’s brother, Khalid bin Salman.
The newspaper said the prince’s brother, who is Saudi ambassador to the United States, told Mr Khashoggi he would be safe in going to the Saudi Consulate in Istanbul to retrieve the documents he needed to get married.
Both the ambassador himself and a spokeswoman for the Saudi embassy in Washington have said that the claim was false.
As we told the Washington Post the last contact I had with Mr. Khashoggi was via text on Oct 26 2017. I never talked to him by phone and certainly never suggested he go to Turkey for any reason. I ask the US government to release any information regarding this claim.
— Khalid bin Salman خالد بن سلمان (@kbsalsaud) November 16, 2018
The ambassador tweeted: “The last contact I had with Mr Khashoggi was via text on Oct 26 2017. I never talked to him by phone and certainly never suggested he go to Turkey for any reason. I ask the US government to release any information regarding this claim.”
In a statement issued to The Associated Press, Fatimah Baeshen, spokeswoman for the Saudi embassy in Washington, said the ambassador met Mr Khashoggi in person once in late September 2017 and they had communicated via text messages but there had never been any phone conversation.
“Ambassador Prince Khalid bin Salman has never had any phone conversations with him,” she said.
“You are welcome to check the phone records and cell phone content to corroborate this – in which case, you would have to request it from Turkish authorities,” she said, adding that Saudi prosecutors have checked the phone records numerous times to no avail.