Mr. Muzaini, the Saudi attaché, was at the consulate when Mr. Khashoggi visited it on Sept. 28; flew later that day to the Saudi capital, Riyadh, and met with the deputy chief of Saudi intelligence, Ahmad Asiri; and returned to Istanbul on Oct. 1 to carry out the assassination the next day, Sabah reported.
The newspaper described Mr. Muzaini as the “black box” of the operation,” and said his movements had been tracked by Turkish intelligence and photographic evidence gathered by the police.
The report was another in a steady stream of anonymous leaks and public statements from Turkish officials over recent weeks that pointed to a premeditated plan at the highest levels of the Saudi government to kill Mr. Khashoggi, undermining Saudi denials and keeping up international pressure on the kingdom to come clean.
On Monday, the Turks leaked images of a Saudi official who resembled Mr. Khashoggi and dressed in his clothes after he was killed, walking around Istanbul, creating a trail of surveillance camera images that appeared to have been intended to support the original Saudi narrative. Saudis briefed on the matter confirmed the ruse.
The use of a look-alike bolstered the Turkish case for premeditation, and at the least, showed an attempt to cover up the killing. On Monday, the spokesman for Mr. Erdogan’s Justice and Development Party, Omer Celik, described the death of Mr. Khashoggi as “monstrously planned.”
Mr. Khashoggi went to the consulate on Sept. 28 to request documents confirming his divorce, so that he could marry his fiancée. Sabah reported that at 2 p.m. that day, Mr. Muzaini flew out of Istanbul’s second airport, Sabiha Gokcen International Airport.
Mr. Khashoggi was killed on Oct. 2 after he returned to the consulate, about 1:15 p.m., to pick up the paperwork he had requested. Mr. Muzaini flew out of Ataturk Airport at 9 p.m. that night, Sabah said.
A team of 15 Saudis who flew to Istanbul on the day Mr. Khashoggi died, several of them with ties to the crown prince, have been identified by Turkish officials as being involved in the killing. They all left the country hours after they had arrived.