Some have speculated that the introduction of this unknown person could allow the Saudis to duck responsibility for the state of Mr. Khashoggi’s corpse if and when it is found. The Saudis could argue they weren’t involved.

Turkish officials said Saturday that they expected to find the body soon.

What is the evidence?

Little concrete evidence has been made public by either side, although the Turks have provided much more detail to back up their narrative than the Saudis have.

The Turkish information included names of the members of the Saudi team and photos of them at the airport, in their hotels and near the consulate. Many of the men have ties to the Saudi military and security services.

The New York Times was able to corroborate the identities of most of the men on the team and to establish that at least four had frequently traveled abroad with the country’s de facto ruler, Crown Prince Mohammed bin Salman, as part of his security detail.

They included Gen. Maher Abdulaziz Mutreb, an intelligence officer who had been photographed near the crown prince during visits to Paris, Madrid, Houston, Boston and the United Nations.

Another suspect, Salah al-Tubaigy, is a renowned Saudi autopsy specialist with ties to the security forces.

The Saudi official confirmed that both were part of the 15-man team, but said that Dr. Tubaigy was tapped not for his expertise in dealing with dead bodies, but rather for his experience in forensics and his skill in removing evidence from crime scenes.