Turkish media reports that could not be verified said investigators had found Mr Khashoggi's belongings in a number of suitcases found in a Saudi consulate vehicle discovered in a auto park in Istanbul.
Saudi officials said Friday, more than two weeks after Khashoggi's disappearance, that the journalist died in a fight at the consulate. "We are seeking answers", Erdogan said.
"It will be revealed in full nakedness", he said in a televised speech.
"Why did these 15 people all with links to the event gather in Istanbul on the day of the murder?". Why were 18 people arrested? "All of this need to be explained". The agents reportedly included several senior Saudi officials and men with close ties to MBS.
Erdogan called Khashoggi's death a "ferocious" murder and suggested that Saudi Crown Prince Mohammed bin Salman (MbS) is hiding information about the killing-noting that he believes Saudi King Salman to be honest in his country's investigation into the case, but making no mention of the prince.
"Jamal told me that his wife was forced to divorce him after she was banned indefinitely from travel", Assiri said, speaking to Middle East Eye from London.
He has twice held telephone talks with King Salman on the crisis, with some analysts arguing Erdogan was seeking to preserve Turkish-Saudi relations through the ageing monarch while sidelining his headstrong son Prince Mohammed. Crown Prince Mohammed bin Salman called Khashoggi's youngest son.
Just days after last year's forum, the emboldened prince launched a sweeping shakedown of Saudi Arabia's wealthiest businessmen and top princes for alleged corruption, transforming the same Ritz-Carlton hotel that had earlier hosted the investment forum into a prison for the country's elite. CCTV footage shows a body double dressed in Khashoggi's clothes leaving the consulate and touring Istanbul's landmarks, undermining the idea that the team interrogating Khashoggi meant to bring him back alive.
Erdogan and his government have still not released the audio evidence they claim to have of Khashoggi's murder.
In an interview with the Washington Post, he said "obviously there's been deception, and there's been lies".
Five employees from the Saudi consulate were testifying to prosecutors on Monday, Anadolu said, with 22 foreign and Turkish workers expected to give statements in total.
"He has very good control".
The secretary of state also told reporters at the State Department that the USA has identified some of the people "who we suspect to be responsible" for Khashoggi's death.
"I do not want to leave Canadians holding a billion-dollar bill because we're trying to move forward on doing the right thing", he added.
"It underscores the determination of our administration to find out what happened", he said. "It could be something in the building went badly awry".