Key to the Turkish investigation could be surveillance footage from the streets adjacent to the consulate. At least six closed-circuit cameras are positioned at the front entrance of the consulate next to its barbed-wire-topped walls. Some of them are maintained by Turkish police.

When Cengiz was first interviewed by police, on the day Khashoggi disappeared, she was presented with a still from one of the cameras that showed him walking in.

“Is this him?” they asked her. She confirmed that it was — in the dark jacket that he had been wearing.

At least four cameras keep watch on the garage and the back entrance. Three more are pointed at the road next to the back entrance, mounted at a primary school across the way. The footage has been retrieved by Turkish intelligence, according to ISS, the firm that handles security at the site.