Saudi journalist Jamal Khashoggi was attacked in the Saudi consulate in Istanbul within two minutes after he entered it and was dead in seven minutes, the New York Times reported.
A person close to Turkish President Recep Tayyip Erdogan revealed "new specificity to the Turkish claims about the speed with which Khashoggi was killed and said (that) it also showed premeditation".
According to the daily, Khashoggi came under attack within two minutes of entering the consulate on October 2 and was dead within seven minutes. He was dismembered in 22 minutes.
Turkish officials have previously said that the Saudi killer team had finished its work and left the consulate within less than two hours.
The Times also said that Saudi agents who killed Khashoggi brought a body double who resembled the dissident and wore his clothes as part of a cover-up.
Turkey leaked security camera video footage on Monday showing the look-alike strolling the streets of Istanbul shortly after Khashoggi had been killed inside the Saudi consulate.
"The inclusion of a body double in the squad is the latest indication that the death of Khashoggi, a Virginia resident and Washington Post columnist last seen on October 2, occurred during a premeditated plot by the Saudis to abduct or kill him and hide what they did."
On Saturday, Saudi Arabia's rulers admitted for the first time that their agents had killed Khashoggi. They said he was accidentally strangled during a brawl that broke out in the consulate as the Saudi agents tried to persuade him to return to the kingdom.
The Saudi officials have also said that Crown Prince Mohammed bin Salman, the 33-year-old de facto ruler of the kingdom, had no knowledge of the mission and that he learned of the killing only two weeks later. But this theory is widely challenged.
The Times quoted a source as saying that Khashoggi's body was rolled into a rug before handing it over.
Although President Erdogan has promised to reveal a truth "in full nakedness" on Tuesday, the daily said he does not intend to disclose the specific evidence other officials have cited.
"Some of that evidence may have been obtained through audio surveillance of the consulate in violation of international agreements..
"But he remains determined to try to assign the blame for the killing to the upper reaches of the Saudi royal court, as close as possible to the crown prince."
Meanwhile, Khashoggi's fiancée, Hatice Cengiz, has been placed under police protection, a Turkish official said.
The step had been taken not because of any specific threat but because Cengiz, who was to marry Khashoggi the day after he went to the Saudi Consulate, had been the target of online abuse, the Times said.