Pro-government Turkish newspaper Yeni Safak, citing the audio, has said his torturers cut off his fingers during an interrogation and later beheaded him.
"The Saudi prosecution pursues its investigations with the suspects in light of the information it received, and in light of its investigation in order to determine the facts, Allah willing, and ensure the pursuit of justice", the Saudi Foreign Ministry added in a statement released via Twitter.
Saudi Arabia first denied any involvement in Khashoggi's disappearance on October 2 but a Saudi official eventually attributed his death at the Saudi consulate in Istanbul to a botched attempt to return him to the kingdom.
British Prime Minister Theresa May told Saudi Arabia's King Salman on Wednesday that his country's explanation of Khashoggi's death in Turkey lacked credibility, her office said.
Saudi Attorney General Saud al-Mojeb announced Thursday that investigators reached that conclusion after Turkish officials presented evidence to them, according to a statement put out by the state-run Saudi Press Agency.
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".
"Haspel, who departed for a secret trip to Turkey on Monday, heard the audio during her visit, according to people familiar with her meetings", said the US daily.
Turkish pro-government media reported Wednesday that Turkish intelligence had shared "all the evidence" from its probe with the CIA. Cavusoglu said Turkey had no intention of taking the Khashoggi case to an global court but would share information if an worldwide inquiry were launched.
Speaking at the investment forum, Prince Mohammed said: "Many are trying to exploit the Khashoggi affair to drive a wedge between Saudi Arabia and Turkey".
Mr Erdogan on Wednesday spoke with Prince Mohammed in their first telephone conversation since the killing, a Turkish presidential source and Saudi state media said.
The journalist was last seen entering the Saudi consulate in Istanbul on October 2.
An unnamed Saudi official told Reuters news agency on Sunday that Khashoggi had died in a chokehold after resisting attempts to return him to Saudi Arabia.
"Justice in the end will appear.". It also contradicts many observers who believe the complex scheme that led to Khashoggi's death could not have occurred without the knowledge of the crown prince, who controls all major levers of power in the kingdom with the blessing of his father, King Salman.
The Trump administration and the USA defence industry are scrambling to save the few actual deals in a much-touted $110 billion arms package for Saudi Arabia.
He said Saudi Arabia had arrested 15 Saudi suspects who flew to Turkey shortly before the attack, as well as three local consulate staff, and called for the 18 to stand trial in Istanbul.
Salah Khashoggi has been barred from traveling since previous year, a friend of the family told The Associated Press. The sources declined to disclose his destination or other details of his departure.