– The participants nicknamed it "Davos in the Desert," which captures the lofty ambitions of the annual investor conference scheduled to convene in Riyadh, Saudi Arabia, this month.

Initially planned as an intimate gathering, it grew quickly in size and scope, and the inaugural meeting in 2017 reflected the determination of its host, Crown Prince Mohammed bin Salman, to be a player on the world stage.

In keeping with Muslim practice, no alcohol was served. Waiters roamed the vast, opulent Ritz-Carlton Hotel, offering pale Saudi coffee and exotic fruit drinks. Outside the hotel, female executives kept their arms and legs covered. But the gathering was an extravagant embodiment of Crown Prince Mohammed's dream to modernize Saudi Arabia and wean it off its reliance on oil by 2030.

Speaking on stage to Fox Business Network anchor Maria Bartiromo, the crown prince said Saudi Arabia "and all of its projects and programs can reach new horizons in the world."

Last week, that vision collided with the brutal realities of the Middle East: a swirl of allegations that Crown Prince Mohammed's family ordered the murder of a Saudi journalist in Turkey. The ensuing furor has tarnished the future king's reputation and left his conference in tatters, as foreign investors confront the dark side of his Arabian dreams.

If the 2017 conference served as a grand coming-out party for Crown Prince Mohammed, this year's gathering is a symbol of the West's deepening disillusionment with the young leader. No longer the bold reformer bent on modernizing his kingdom — a favorite of President Donald Trump and his son-in-law, Jared Kushner — he is now regarded as an impulsive, unreliable autocrat who falls back on crude tactics to crush dissent.

The grisly, if unconfirmed, reports about the journalist, Jamal Khashoggi, have prompted a growing list of attendees and sponsors to bail out of the Riyadh meeting. By week's end, the New York Times and every other major Western news media organization, except Fox Business Network, had canceled its participation.

The chief executive of Uber, Dara Khosrowshahi, was the most dramatic withdrawal. In an anguished phone call late last week with the conference's sponsor, Yasir Al Rumayyan, Khosrowshahi, who is Iranian-American, told him that the allegations about Khashoggi were "terrible," and that he would not go to Riyadh unless the questions about his fate were cleared up, according to two people briefed on the conversation.

Al Rumayyan, whose Saudi fund has invested more than $3.5 billion in Uber and who holds a seat on the company's board, tried to assure him that the reports were not true, these people said, in keeping with the Saudi government's denial of any involvement in Khashoggi's disappearance. But it did not change his decision.

Other institutions with ties to Saudi Arabia, such as lobbying firm Harbour Group and the Brookings Institution, have also terminated their relationships.

"Mohammed bin Salman tried very hard over more than 3½ years to fashion an image of himself as a reformer and even a revolutionary," said Bruce O. Riedel, an expert on Saudi Arabia at Brookings. "Now that veil has been torn apart."

That leaves many financiers and technology executives in a deeply awkward position. Some have made multibillion-dollar investments in Saudi Arabia; others are managing billions of dollars of Saudi money. They want to keep the money flowing, even if they cringe at lending their names or prestige to Crown Prince Mohammed's gathering.

Several of the investors with the biggest stakes in Saudi Arabia — including Stephen Schwarzman, chief executive of the Blackstone Group; Jamie Dimon, chief executive of JPMorgan Chase; and Masayoshi Son, founder and chief executive of SoftBank — have yet to cancel their plans to attend.

"There will still be a lot of serious people in Riyadh," said Jon B. Alterman, director of the Middle East Program at the Center for Strategic and International Studies. "Investors are going to be interested in Saudi Arabia for a long time to come," he said, pointing to its extraordinary wealth and the fact that oil prices are more than $80 a barrel.

Treasury Secretary Steven Mnuchin is still scheduled to represent the Trump administration, though on Friday, Trump told reporters that he might reconsider that decision. He said he planned to call King Salman to press him for answers about Khashoggi.

Trump played an important role in anointing Crown Prince Mohammed as an attractive investment. He backed the 33-year-old prince when he was jockeying to be his father's heir, played host to him at a White House lunch, clinched a multibillion-dollar arms deal with his military, and chose Riyadh for his first foreign destination as president.

In April, Crown Prince Mohammed took a three-week tour of the United States that doubled as a road show for Saudi Arabia. After conferring with Trump in the Oval Office, he met with Bill Gates and Jeff Bezos in Seattle, Morgan Freeman and Dwayne Johnson in Hollywood, and Richard Branson in the California desert, where the two discussed space travel.

Last week, Branson suspended his directorship at two tourism projects near the Red Sea and halted discussions about an investment in his space ventures by Saudi's sovereign wealth fund, the Public Investment Fund, which sponsors the conference.

Unlike Davos, the conference in Switzerland that draws a roster of the world's wealthy and prominent, the Saudi event has struggled to attract heads of state. In 2017, former Prime Minister Tony Blair of Britain and former President Nicolas Sarkozy of France attended.

In retrospect, clouds were gathering on the horizon. A few days after the foreigners checked out of the Ritz-Carlton, Crown Prince Mohammed converted it into a high-end prison for hundreds of wealthy Saudis. For weeks, guards kept them locked up — roughing up some — until they handed over billions of dollars in what the prince insisted were ill-gotten gains.

Steven A. Cook, an expert on Saudi Arabia at the Council on Foreign Relations, said the conference, like Crown Prince Mohammed's decision to allow women to drive, was calculated to put an appealing face on a ruthless attempt to transform his society.

"These were ways of building constituencies that would be a cushion against opposition from vested interests in the royal family," Cook said. "This was all a way of signaling to this small elite that he's got the support of all these people around the world."

"Now," he said, "we're coming to grips with the fact that he's the big dog."