The sources have told british Sky News the Saudi dissident had been "cut up" and his face "disfigured".
One source also suggested the writer's remains were discovered in the garden of the Saudi consul general's Istanbul home - located around 500 metres away from the consulate.
In a speech to the country's parliament, Turkey's president Erdogan demanded Saudi Arabia hold those responsible to account and asked: "Why has the body of someone who was officially said to be killed not been found yet?"
He did not mention an alleged audio recording that Turkish authorities claim to have of Mr Khashoggi's death that supposedly confirms he was tortured, killed, had his fingers cut off and was dismembered.
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Saudi King Salman and crown prince meet Khashoggi family members
The Saudi king and his son Crown Prince Mohammed bin Salman received family members of murdered Washington Post contributor Jamal Khashoggi in Riyadh on Tuesday, state news agency SPA reported.
The royals greeted two of the journalist's sons, Salah and Sahel, at the Yamama Palace in Riyadh. A friend of the Khashoggis' has told The Associated Press that Salah is under a travel ban. The individual spoke to the A.P. on condition of anonymity, fearing reprisal.
