The crown prince said Saudi Arabia and Turkey would work together "to reach results" in their joint investigation into Khashoggi's death, and he described cooperation between the two countries as "special".
Turkish President Recep Tayyip Erdogan has said the "savage murder" of the journalist was meticulously planned, and demanded that all those linked to the killing face punishment.
President Trump, who has made Saudi Arabia a central pillar of his Middle East strategy, has grown increasingly skeptical of the kingdom's claim that Khashoggi's death was a "rogue operation" that occurred after a fistfight broke out in the Saudi Consulate in Istanbul on October 2.
Following a global outrage, Riyadh acknowledged that Khashoggi was killed in a fistfight inside the consulate after an interrogation went wrong.
At first, Saudi officials said he had left the building and they did not know his whereabouts.
According to the report, a person who is familiar with the audio said it was "compelling" and could put more pressure on the U.S. to hold Saudi Arabia accountable for Khashoggi's murder.More news: Horner Blames Renault for Ricciardo Issues
He seemed relaxed on the panel he shared with Bahrain's Crown Prince Salman bin Hamad al-Khalifa and Lebanon's Prime Minister Saad al-Hariri.
Martin Indyk, a top Middle East policymaker under Bill Clinton, said President Donald Trump had in effect tried to subcontract policy in the region to Saudi Arabia and Israel as he lessens United States commitments.
Many countries responded with skepticism to the version of a brawl involving Khashoggi and rogue officials, putting Saudi Arabia on the defensive even as it hosted an investment conference this week that many dignitaries skipped because of the scandal. A Turkish official said the Washington Post report was accurate. Secretary of State Mike Pompeo said the State Department would revoke visas for 21 Saudis the USA had identified as being part of the operation at the Saudi consulate in Istanbul.
That has included identifying a Saudi forensics specialist who is an expert in mobile autopsies that had traveled to Istanbul the day Khashoggi was planning to visit the consulate and pictures of Saudi diplomatic vehicles scouting wooded areas in the days before Khashoggi disappeared.
Meanwhile, the Saudi King Salman bin Abdulaziz Al Saud ordered on Saturday the reorganization of the intelligence authority and sacked senior intelligence as well as other officials over the case.More news: LeBron James came up clutch in his last game against Denver
He said Saudi authorities were working with Turkey on the case.
The crown prince, Saudi Arabia's de facto ruler, said, "Those behind this crime will be held accountable.in the end justice will prevail".
Turkey's state-run news agency also reported Wednesday that Saudi officials had prevented Turkish police from searching a water well in the consulate garden in Istanbul's Levent district.
The departure of Khashoggi's son, Salah, comes after Saudi King Salman and the crown prince met him and the slain journalist's brother Sahel at the royal palace in Riyadh on Tuesday.
On Tuesday there were similar conflicting reports over whether Khashoggi's belongings had been found in suitcases in a Saudi diplomatic auto.More news: Rockets Offering Whopping ‘Renewed Bid’ For Jimmy Butler