The CIA has concluded that Saudi Crown Prince Mohammed bin Salman personally ordered the killing of journalist Jamal Khashoggi, despite the Saudi government’s denials that the de facto ruler was involved, according to a senior US official.

The official told CNN on Friday the conclusion was based on a recording provided by the Turkish government and other evidence, including American intelligence.

Investigators also believed that an operation such as the one that ended in Khashoggi’s death would not have happened without Salman’s knowledge given his control of the government, the official said.

Reacting to the development, a Saudi Embassy spokeswoman said that “the claims in this purported assessment are false. We have and continue to hear various theories without seeing the primary basis for these speculations”.

The Central Intelligence Agency is yet to make an official announcement.

Meanwhile, Turkish President Recep Tayyip Erdogan and his US counterpart Donald Trump on Friday agreed on the need to prevent a cover up of journalist Khashoggi’s murder, a Turkish presidential source said after a phone call between the two leaders.

Turkish media claimed Ankara has more evidence, including a second audio tape discrediting Saudi Arabia’s version of Khashoggi’s killing.

Erdogan and Trump “agreed to shed light on the Jamal Khashoggi murder in all its aspects and that any cover up of the incident should not be allowed,” the presidential source said.

The phone call came a day after Saudi prosecutors announced death penalty charges against five men and the US placed sanctions on 17 suspected of involvement.

They however rejected allegations that the kingdom’s powerful Crown Prince Mohammed bin Salman directed the murder.

Dozens of people meanwhile paid homage to Khashoggi at a symbolic funeral in Istanbul on Friday.

In the absence of a body, the crowd gathered at Fatih mosque in front of an empty platform traditionally reserved for the coffin.

Supporters from the newly-formed Jamal Khashoggi Friends Association were among the mourners.

Khashoggi, a columnist for The Washington Post and also former Saudi royal insider who became a critic of the country’s government, went missing on October 2 after he visited the Saudi consulate in Istanbul to obtain papers for his upcoming marriage.

(With inputs from agencies)