Virgin Group founder Richard Branson has joined such prominent Western business leaders as technology investor Steve Case and Uber CEO Dara Khosrowshahi in backing away from projects with Saudi Arabia after the disappearance and alleged killing of journalist Jamal Khashoggi.

Turkish officials reportedly have told the U.S. government that they have audio and video recordings proving the Washington Post columnist and dissident was killed inside the Saudi consulate in Istanbul this month. The alleged slaying threatens to derail efforts by Saudi Crown Prince Mohammed bin Salman to portray Saudi Arabia as a more open and tolerant place to visit, invest in and do business.

The 33-year-old crown prince hopes to grow his country's $500 billion sovereign wealth fund -- pounded by falling oil prices earlier this decade -- into a $2 trillion global investment fund over the next dozen years.

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Branson said he is suspending his work overseeing two Saudi tourism projects as well as talks with the kingdom's sovereign wealth fund about possible investments in his space ventures Virgin Galactic and Virgin Orbit.

Branson wrote Thursday in a blog post:

I had high hopes for the current government in the Kingdom of Saudi Arabia and its leader Crown Prince Mohammed bin Salman, and it is why I was delighted to accept two directorships in the tourism projects around the Red Sea. I felt that I could give practical development advice and also help protect the precious environment around the coastline and islands. What has reportedly happened in Turkey around the disappearance of journalist Jamal Khashoggi, if proved true, would clearly change the ability of any of us in the West to do business with the Saudi Government. We have asked for more information from the authorities in Saudi and to clarify their position.

Technology executive Case was among those echoing Branson's move, with the AOL co-founder canceling plans to address a conference co-hosted by the Saudi kingdom's sovereign wealth fund in Riyadh later this month.

I was looking forward to returning to Riyadh this month to speak at the Future Investment Initiative conference, and participate in a Red Sea Project meeting. In light of recent events, I have decided to put my plans on hold, pending further information regarding Jamal Khashoggi. — Steve Case (@SteveCase) October 11, 2018

Uber Chief Executive Khosrowshahi also said he would bow out of the Future Investment Initiative conference, a three-day affair scheduled to begin Oct. 23 that has dozens of business executives on its agenda as speakers, according to its website.

"I'm very troubled by the reports to date about Jamal Khashoggi. We are following the situation closely, and unless a substantially different set of facts emerges, I won't be attending the FII conference in Riyadh," Khosrowshahi said in a statement to CBS MoneyWatch.

Saudi Arabia's sovereign wealth fund invested $3.5 billion in Uber two years ago.

Other prominent executives cancelling plans to attend the conference, unofficially billed as "Davos in the Desert," are Viacom CEO Bob Bakish and Los Angeles Times owner Dr. Patrick Soon-Shiong, according to their spokespersons.

I’m terribly distressed by the disappearance of journalist Jamal Khashoggi and reports of his murder. I will no longer be participating in the Future Investment Initiative in Riyadh. — Andrew Ross Sorkin (@andrewrsorkin) October 11, 2018

JPMorgan Chase did not immediately respond to requests for comment as to whether CEO Jamie Dimon still planned to attend the event.

Concerns about Khashoggi had a host of media outlets also backing off the conference.

CNBC anchor and New York Times columnist Andrew Ross Sorkin also said he would not be participating. The Times has pulled out as a media sponsor of the conference, as did CNBC. The Financial Times said it would not be a partner of the event while the journalist's disappearance "remains unexplained."

One person who does plan to attend the conference: U.S. Treasury Secretary Steven Mnuchin. He told CNBC on Friday that the administration is "concerned about what is the status of Mr. Khashoggi. If more information comes out and changes, we could look at that, but I am planning on going."