Saudi prosecutor arrives in Istanbul for Khashoggi investigation

Prosecutor Sheikh Saud al-Mojeb landed at Istanbul's Ataturk Airport on a private jet - just like the 15-man hit squad that allegedly killed Khashoggi did over three weeks ago.

Al-Mojeb is expected to meet with Istanbul chief prosecutor Irfan Fidan and visit the Saudi consulate where Khashoggi was killed. 

The case has brought near unprecedented international scrutiny on Saudi Arabia, which is seeking to draw a line under the crisis after offering a series of differing narratives in the weeks following Khashoggi's murder.

The 59-year-old Washington Post contributor, who had criticised Saudi Arabia's powerful Crown Prince Mohammad bin Salman, vanished after entering the Saudi consulate on 2 October to obtain paperwork for his marriage to his Turkish fiancee.

Gruesome reports in the Turkish media have alleged he was killed and dismembered by a team sent from Saudi Arabia to silence him.

The Saudi prosecutor travelled to Istanbul after acknowledging last week that the killing was "premeditated", based on the evidence of a Turkish investigation.

US Defence Secretary Jim Mattis said on Sunday that Saudi Foreign Minister Adel al-Jubeir had vowed Riyadh would conduct a "full" investigation. 

"We discussed it... the need of transparency, full and complete investigation. Full agreement from FM Jubeir, no reservations at all," Mattis said. 

Saudi authorities have arrested 18 men over the murder and President Recep Tayyip Erdogan has requested they be extradited for trial in Turkey.

Riyadh has dismissed the request, saying they will be prosecuted in Saudi Arabia.

The body of Khashoggi, who was once an insider in Saudi royal circles, remains missing.