But so far, no "smoking gun" has emerged definitively showing Mohammed knew about or ordered the operation, these officials said, and Saudi officials deny that the crown prince was in any way responsible for Khashoggi's death.
The New York Times first reported on the phone call that relayed the message that Khashoggi had been killed.
The Turkish Government allowed US CIA Director Gina Haspel to listen to the audio recording of events that took place inside the consulate and to the telephone conversations that took place between the team and Saudi Arabia, a senior Turkish official said. US officials have heard a recording of the call in which a "boss" is referred to, one person familiar with the matter said.
Turkey also thinks the US has information, possibly including intercepted Saudi communications, beyond what Turkish intelligence has gathered, the person said.
Speaking on the sidelines of a regional summit in Singapore, Bolton said that he has not listened to the recording himself but that "those who have listened to it" assess that it does not implicate Saudi Arabia's de facto ruler. The crown prince's father, King Salman is formally the head of the country.
Saudi officials said the Turks have not provided audio to them that includes the phrase "tell your boss".
"We categorically deny the reporting referencing the crown prince in this matter or that he had any knowledge whatsoever of it," a Saudi official said. "Despite our multiple requests, the Turkish authorities have not provided us with the recordings. However, they allowed our intelligence services to hear recordings, and at no moment were there any references to the mentioned phrase in those recordings."
Saudi Arabia has not been entirely forthcoming with information about the role of its citizens in the killing, according to a Turkish official.
Although Saudi Arabia sent its senior prosecutor to Turkey last month for what it called a "joint" investigation, the Saudis shared no information and appeared only interested in learning what the Turkish investigators knew, the official said.
Since the prosecutor's return to Saudi Arabia, the kingdom has not responded to Turkish requests for information on 18 Saudis arrested in the case, including the results of any interrogations of those detained. That includes information on the disposal of Khashoggi's remains, which have not been found.
Bolton's comments playing down the phone call as a link to Mohammed reflect Trump's own resistance to blaming the crown prince for the journalist's death.
Trump has indicated to aides that he is inclined to accept the official Saudi explanation that rogue operative killed Khashoggi without Mohammed's knowledge.
The Saudi version of events has changed over time. Initially, the kingdom said that Khashoggi left the consulate, after stopping in to obtain documents he needed for his marriage and that it had no knowledge about where he went subsequently.
But as evidence from flight manifests and video surveillance mounted, including footage of personal security guards for the crown prince at the consulate, the Saudi Government acknowledged the killing but blamed it on a group of outliers.
Trump has repeatedly emphasised the importance of maintaining a close relationship with Saudi Arabia, the world's largest purchaser of US defence equipment.
