Turkish investiagtors have for days been scouring the consulate, the consul-general's house and woodland areas on the city's outskirts for Khashoggi's remains.
He took a cab to Istanbul's famed Sultan Ahmed Mosque - popularly known as the Blue Mosque - a few hours after Khashoggi was seen entering the consulate, according to CNN.
Mr Khashoggi, 59, went missing on that same day after entering the kingdom's office.
"That is unacceptable in any government", al-Jubeir said on Sunday.
It said the investigations had "revealed that the discussions that took place between [Khashoggi] and the persons who met him.at the Saudi consulate in Istanbul led to a brawl and a fist fight".
Comments from Saudi Foreign Minister Adel al-Jubeir on Sunday were some of the most direct yet from Riyadh, which has given multiple and conflicting accounts about Khashoggi's killing on October 2, first denying his death and later admitting it amid an worldwide outcry.
The Saudis' greatest concern is the United States, a crucial military ally against archrival Iran and a key source of the kind of foreign investment they will need to reform the economy.
The minister, Retno Marsudi, told reporters that "the president is deeply concerned with the Khashoggi case and Indonesia hopes that the ongoing investigation will be transparent and meticulous". After weeks of denying knowledge of his fate, Saudi officials said Saturday the prominent journalist was killed in a "rogue operation".
But analysts say even if Beijing is hoping to move closer to the Middle East kingdom in the event of sanctions being applied, ties between Washington and Riyadh remain strong - and China's role in the region would be limited.
Surveillance footage allegedly provided by Turkish authorities to CNN purports to show Khashoggi's lookalike, named as Mustaka al-Madani, leaving the Saudi Consulate in Istanbul via the rear entrance, wearing the journalist's own clothes that he wore on October 2.
The report by Yeni Safak on Monday cited no source for the information. South Carolina Sen. Lindsey Graham said Sunday "I find it impossible to believe that the Crown Prince was not involved".
"It will not have any positive consequences if we halt arms exports but other countries at the same time fill the gap", he said.
He reiterated Chancellor Angela Merkel's statement from Sunday, saying Berlin "at this stage will not approve further arms exports because we want to know what happened", adding that "all explanations so far have been unsatisfactory".
"Only when all European nations are in agreement will this make an impression on Riyadh", he said, speaking on public television.
"We're getting as many facts as we can", Kushner said, "then we'll determine which facts are credible".
One member of the 15-man team suspected in the death of Jamal Khashoggi dressed up in his clothes and was captured on surveillance cameras around Istanbul on the day the journalist was killed, a senior Turkish official has told CNN.
King Salman likewise called Khashoggi's son, Salah. Saudi Arabia is Germany's second-largest weapons customer, according to official data reported by German news agency DPA. The kingdom finally acknowledged his death early Saturday in what it described as a "fistfight".