Trump told reporters he'd spoken to the Saudi king, who assured him they had not ordered Khashoggi's extermination, and suggested helpfully it may have been the work of a "rogue killer". "We're going to get to the bottom of it and there will be severe punishment", Trump said.
"I am immediately sending our Secretary of State to meet with King!", Trump wrote.
The Turkish government has also told the Trump administration that it possesses audio recordings of what occurred inside the consulate that day - evidence that US officials said supports the conclusion that Khashoggi was interrogated, tortured and then murdered.
The decision to dispatch Pompeo signals how much the crisis over the fate of Khashoggi, a Saudi citizen and USA resident who wrote critically of the kingdom's leaders, is threatening to damage USSaudi relations. Until now, Riyadh has not allowed Turkish investigators to search the consulate - officially Saudi territory - with reports both sides were at odds over the conditions. "So we're going to have to see", Trump said in a "60 Minutes" interview broadcast Sunday.
"The king firmly denied any knowledge of it", Trump said.
Meanwhile, Arabic channel Al-Jazeera quotes Turkey's attorney-general's office as saying it has found evidence to back claims that Mr Khashoggi was killed inside the mission.
On that same day 15 other Saudis, including several officials, arrived in Istanbul on two planes and visited the diplomatic building while Khashoggi was also inside, Turkish police sources said.
Saudi officials have called all the allegations "baseless", but have offered no evidence the journalist left the consulate.
Pompeo met with Saudi Arabian King Salman and the crown prince in Riyadh on Tuesday.
Trump then said that the Saudi government's denial "could not have been stronger".
The World Bank, The New York Times, Bloomberg, CNBC and Uber have also announced their decision to pull out the conference amid the ongoing scandal around Khashoggi's disappearance. The journalist, who has written for The Washington Post, is known to be critical of the Saudi government.
Khashoggi's disappearance has caused global furor and created a rift between the USA and Saudi Arabia.
Khashoggi went missing after entering the Saudi consulate in Istanbul earlier this month. The intervention of the king comes soon after some Saudi officials threatened retaliation against any country that took punitive measures against the kingdom.