Forensics tests like spraying luminol, a chemical mixture, can expose blood left behind, said Mechthild Prinz, an associate professor at the John Jay College of Criminal Justice who previously worked at the New York City's Office of the Chief Medical Examiner.
Earlier, the joint Saudi-Turkish working group conducted a nine-hour inspection of the Saudi Consulate building, during which the police reportedly obtained some evidence relevant to the Khashoggi case proving that the journalist never left the building.
In an interview with CBS late last week, US President Donald Trump, in turn, pledged "to get to the bottom" of the Khashoggi case, warning that if Saudi authorities are behind all this, the US would impose "severe punishment" on them.
Saudi Arabia has denied any role in Khashoggi's disappearance.
Khashoggi, a columnist for the Washington Post, vanished on October 2 after he entered the Saudi consulate in Istanbul to obtain a marriage document. Trump's comments followed a phone call with King Salman in which Trump said he strongly denied any knowledge of what happened to the journalist.
The New York Times, citing a person familiar with the Saudi plans, reported the crown prince had approved an interrogation or rendition of Khashoggi back to Saudi Arabia.
What evidence Turkish officials gathered at the consulate remains unknown.
Turkey had wanted to search the consulate for days.
Members of the United States congress - both Democrat and Republican - could vote to block arms sales to Riyadh, and the White House would be under pressure to punish Saudi individuals if they were proven to have played a role in Khashoggi's disappearance. Certain areas of the consulate were to remain off-limits, although officials would be able to inspect surveillance cameras, Turkish media reported.
Dozens injured as hurricane Leslie strikes Portugal
Leslie was dubbed a "zombie" hurricane as it first formed on September 23, only to meander through the Atlantic Ocean for weeks. But in the coastal town of Figueira da Foz, Leslie's wind speeds reached up to 170 km/h, state broadcaster RTP said.
"It's all about posturing to give them time to find a solution", he said.
The Foreign Ministry official spoke on condition of anonymity in line with government regulations.
Khashoggi has criticized Saudi Arabia's war in Yemen, its recent diplomatic spat with Canada and its arrest of women's rights activists after the lifting of a driving ban for women-policies seen as initiatives of the crown prince.
Prince Mohammed has aggressively pitched the kingdom as a destination for foreign investment. Under intense pressure from Washington and business leaders around the world, Riyadh now appears to be preparing to acknowledge that Mr Khashoggi was in fact killed inside the consulate.
Trump dispatched Secretary of State Mike Pompeo to meet King Salman over the case that has strained the Americans' relationship with the Saudis, carefully cultivated by the USA president.
They include the CEO of Uber, a company in which Saudi Arabia has invested billions of dollars; billionaire Richard Branson; JPMorgan Chase & Co.
Prince Mohammed, 33, a son of King Salman, consolidated his control in June 2017 when he was named Crown Prince to replace his cousin, Mohammed bin Nayef, who was sacked.
Meanwhile, the chiefs of Blackstone and BlackRock, two major USA investment firms, joined an exodus of executives pulling out of Crown Prince's "Davos in the Desert" summit.
The US president has also been counting on Riyadh to plug any gap in world oil supplies as he prepares to reimpose a second tranche of crippling sanctions against Tehran in November following his abandonment of a landmark 2015 nuclear deal.