A Saudi source at the consulate has denied that Khashoggi had been killed at the mission and said that the accusations were baseless. He has not been heard from since October 2, when he entered a Saudi Arabian consulate in Turkey to receive marriage paperwork.
Istanbul prosecutors are investigating the incident, while the consulate said on Twitter that it was working in coordination with Turkish authorities. Friends and officials have blamed Riyadh for the dissident journalist's disappearance and alleged murder.
Meanwhile on Tuesday, the Washington Post - where Khashoggi wrote columns after fleeing Saudi Arabia over fears of retribution for his critical commentary - reported U.S. intelligence intercepted communications of Saudi officials planning to abduct the prominent journalist.
DailyMail.com said a friend of the journalist revealed that Mr Khashoggi's encrypted messages had been read after he vanished.
He has not been heard of since.
After several of his friends were arrested, his column was cancelled by the al-Hayat newspaper and he was allegedly warned to stop tweeting, Mr Khashoggi left Saudi Arabia for the United States, from where he wrote opinion pieces for the Washington Post and continued to appear on Arab and Western TV channels. "Canadian officials are actively seeking more information", Adam Austen, a spokesman for Canadian Foreign Minister Chrystia Freeland.More news: Florida Panhandle pummeled by record-breaking Hurricane Michael
"Diplomats get absolute immunity from criminal prosecutions, so if an ambassador was involved in the murder, they can't be touched", Professor Saul said.
That Saudi Arabia would allow foreigners to enter a consulate and search it shows the growing global pressure the kingdom faces over the disappearance of Mr Khashoggi, a critic of Saudi Arabia and contributor to the Washington Post.
But Dalay, a non-resident fellow at Brookings Institution, said Turkish officials do not want the case to be seen as "politicised from the start".
TRT World's Ben Tornquist reports.
Khashoggi, an Al Watan and Washington Post journalist known for his strong critiques of authorities in Saudi Arabia and ruling Prince Mohammed bin Salman, had fled his home country past year to live in self-imposed exile in the United States. He told her to call an adviser to Turkish President Recep Tayyip Erdogan if he did not return. The consulate insists Khashoggi left its premises, contradicting Turkish officials. Donald Trump commented on the disappearance in his press conference yesterday, saying "I do nor like it" and expressing hope that the issue will "sort itself out".
Yemeni Nobel Prize victor Tawakkol Karman, centre, participates at a demonstration for Khashoggi that was organized by the Turkish-Arabic Media Association in front of the Saudi Arabian Consulate in Istanbul on Friday.More news: Wall Street dives, setting the ASX up for heavy losses at open
He has also criticised Saudi Arabia's role in Yemen, where Riyadh leads a military coalition fighting alongside the government in its war with Iran-backed rebels.
He also said what happened to Khashoggi was a crime and those responsible for his disappearance must be tried, Al Jazeera said. "The consulate officials can not save themselves by simply saying, 'He has left, '" Erdogan told a news conference in Budapest, where he is on an official visit.
"The condition of the lost journalist, details on him and who is responsible for this will be uncovered", Omer Celik said.
Khashoggi was right about Saudi repression.
Khashoggi left Saudi Arabia past year saying he feared retribution for his criticism of Saudi policy over the Yemen war and its crackdown on dissent, and since then wrote columns for the Washington Post newspaper. "I can speak when so many cannot".
Last week, Crown Prince Mohammed told Bloomberg News that his government was "very keen to know what happened to him", and that Mr Khashoggi had left "after a few minutes or one hour". We look at the media and see various reports that make us think about it.More news: Jamal Khashoggi: Trump condemns Saudi writer's disappearance