'Where is the body?'
Galip Dalay, visiting scholar at University of Oxford, stressed the significance of Erdogan's speech.
"The most important thing is that Erdogan confirmed everything we sort of heard through other channels," he told Al Jazeera. "However, now it's no longer attributed to unnamed Turkish officials, but it's the president of Turkey who has confirmed what has happened," Dalay said.
Erdogan also demanded answers on what happened to Khashoggi's body, mentioning reports that a local cooperator allegedly disposed of it.
"Where is the body? There are claims his body has been given to a local person, but who is this local person," Erdogan asked.
"Nobody is allowed to think this case will come to an end without answering all these questions," he added.
The Turkish president also said Saudi Arabia was taking the right steps by working with Ankara on the investigation and carrying out the 18 arrests.
Dalay, who is also a non-resident fellow at Brookings Institution Doha, underlined Erdogan's "distinction" in his speech between King Salman and his son, the powerful Crown Prince Mohammed bin Salman (MBS).
"Everything that Erdogan provided pointed towards MBS, without naming the crown prince specifically," said Dalay, adding that the Turkish president was clearly trying to prevent a full-blown crisis between Ankara and Riyadh.
On Sunday, speaking in an exclusive interview with Fox News, Saudi Arabia's Foreign Minister Adel al-Jubeir said Khashoggi's killing inside the consulate was "a terrible tragedy" and that MBS had nothing to do with it.
Taha Ozhan, research director at the Ankara Institute, told Al Jazeera that he thought Erdogan was taking the right steps.
"The Saudis know very well what Turkey knows, and what Erdogan has been doing is the right thing, namely asking the Saudis for full cooperation in this case."[mr/aje]