"Based on their initial findings, the police believe that the journalist was killed by a team especially sent to Istanbul and who left the same day", the official told AFP on Saturday. Saudi authorities early Sunday called the allegation "baseless".
Saudi Consul-General Mohammad al-Otaibi told Reuters on Saturday that the consulate's own security cameras showed only a live stream and did not record footage, so they could not provide evidence of Khashoggi's movements.
The Chief Public Prosecutor's Office in Istanbul initiated an investigation on the day of the incident while the consulate also said on Twitter that it was working in coordination with Turkish authorities. The channel was on air for less than 11 hours before it was shut down.
Mr Khashoggi, who will be 60 on 13 October, was born in the western Saudi city of Medina, which is revered in Islam as the burial place of the Prophet Muhammad.
Khashoggi had gone to the consulate to obtain documents needed to marry his Turkish fiancee.
Two months later, writing about the detentions of scores of Saudi royals, senior officials and businessmen accused of corruption, he said Crown Prince Mohammed bin Salman dispensed "selective justice" and said there was "complete intolerance for even mild criticism" of the crown prince.
"Jamal was - or, as we hope, is - a committed, courageous journalist", the director of The Post's editorial page said.She said he never left the consulate. I believe that people championing freedoms, freedom of thought will not let this case to be closed and will monitor it.
The 33-year-old crown prince, who was named heir to the throne in June 2017, has garnered global attention with his rapid rise to power as well as social and economic reforms.
That relationship is already strained over several issues, including Turkey's support for Qatar in the blockade by Saudi Arabia; its closeness to the Muslim Brotherhood - blacklisted by Riyadh as a terrorist organisation; and its rapprochement with Saudi Arabia's arch-rival Iran. They included a friend of Khashoggi who was had just returned from a trip to the U.S.as part of an official Saudi delegation. Its billionaire backer was detained in the Ritz Carlton roundup overseen by Prince Mohammed in 2017.
If his killing is confirmed, it could prompt a decisive change in how the United States deals with Saudi Arabia.
The dispute over Khashoggi's disappearance also threatens to reopen rifts between Ankara and Riyadh.
U.S. Sen. Chris Murphy, the Connecticut Democrat who sits on the Senate's Committee on Foreign Affairs, expressed shock over the news.
There has been a Twitter uproar on social media by political activists and opinion writers talking about they called the "exposed play", and the odd Muslim Brotherhood supporters who tweeted that Khashoggi died two days ago, which was seen by many to expose the systematic and deliberate game.
Press freedom groups likewise have decried Khashoggi's disappearance.
"We are not in a position to confirm these reports, but we are following them closely", the official said.
"If Saudi authorities wish to counter these claims, they must produce Khashoggi immediately". She added that she was waiting for official confirmation as the allegations circulated.