Saudi Arabia, an oil rich monarchy and staunch US ally, has long relied on its financial largesse to persuade partners to support its foreign policy objectives.
Western diplomats suspect that the kingdom will also compensate Turkey for its willingness to launch a joint investigation on Khashoggi's disappearance - a payback that could come in the form of large-scale debt relief, strategic buyouts or other arrangements that boost Turkey's ailing economy.
Khashoggi's disappearance has hurt the reputation of Saudi Arabia's crown prince, Mohammed bin Salman, whose close relationship with US President Donald Trump's son-in-law and senior adviser Jared Kushner has put him at the centre of the Administration's Middle East policy.
Turkish authorities say Khashoggi was killed on October 2 during a visit to the Saudi consulate in Istanbul to obtain a document required to get married.
Trump initially promised "severe punishment" for Saudi Arabia if the United States determined that Saudi agents killed Khashoggi. But the President has since floated an alternative theory involving "rogue killers" and compared the case to the sexual assault allegations against recently confirmed Supreme Court Justice Brett Kavanaugh.
"Here we go again with you know you're guilty until proven innocent," Trump told AP in an interview.
During Pompeo's visit to Saudi Arabia, the top diplomat and the crown prince smiled for the cameras and emphasised the two countries' mutual interests. When asked if he had learned any details about Khashoggi's disappearance, Pompeo told reporters that "I don't want to talk about any of the facts; they didn't want to, either, in that they want to have the opportunity to complete this investigation in a thorough way."
The Saudi payment to support stabilisation efforts in Syria is a cornerstone of Trump's "America First" strategy, which calls on regional countries to take on a greater burden for security challenges, including Syria. In August, US officials hailed the Saudi pledge and said the United States would use US$230 million earmarked to help stabilise Syria for other purposes.
McGurk, the State Department envoy, arrived in Saudi Arabia on Saturday to discuss how the US$100 million in stabilisation money would be spent, said a State Department official.
The official said the timing was a coincidence, and that transferring the US$100 million "has multiple steps all of which clicked through over the past two months."
Middle East experts said the timing of the transfer likely sent a clear message to the Trump Administration.
"In all probability, the Saudis want Trump to know that his cooperation in covering for the Khashoggi affair is important to the Saudi monarch," said Joshua Landis, a professor at the University of Oklahoma. "Much of its financial promises to the US will be contingent on this cooperation."
The Saudi Embassy in Washington did not respond to requests for comment.
