After investigations at the Saudi consulate and the consul's residence, Turkish authorities have widened the geographic focus of the search, the senior Turkish officials said. Investigators tracked the routes and stops of cars that left those two places on Oct. 2, the officials said.

Khashoggi's killers may have dumped his remains in Belgrad Forest adjacent to Istanbul, and at a rural location near the city of Yalova, a 90-kilometre (55 mile) drive south of Istanbul, the officials said.

"The investigations led to some suspicion that his remains may be in the city of Yalova and the Belgrad forest, police have been searching these areas," one of the officials said, speaking on condition of anonymity. A "farm house or villa" may have been used for the disposal of remains, the official said.

The pro-government Sabah newspaper published a series of photos of a man it identified as someone who travels with the Saudi crown prince. The time-stamped photos showed the man outside the Saudi consulate building in Istanbul on the morning Khashoggi disappeared, Sabah said.

Khashoggi went to the consulate seeking documents for his planned marriage to his Turkish fiancee, who was waiting outside, and was never seen again.

Reuters