Galip Dalay, a visiting scholar at the University of Oxford, was appearing on the BBC’s Newsnight programme when he spoke about the murder of his friend Mr Khashoggi.
Mr Dalay claimed the attack on Mr Khashoggi could not have happened without the Saudi monarchy’s authorisation.
He said: “By now it is clear what has happened.
“It is a gruesome murder. It is a horrendous killing of a very gentle personality, an intellectual and a journalist.
“It was intended, it was premeditated and it is state-sanctioned.”
Mr Dalay urged viewers of the programme to “think about the nature of this murder” and the fact “close and personal aides” of Crown Prince Mohammad bin Salman (MBS) were involved.
The academic explained it was “now well established” 15 people had arrived in Istanbul with the sole purpose of killing Mr Khashoggi and Saudi diplomats had been fully aware of the heinous crime.
He said: “It is well-established that the murder was conducted inside the consulate in Istanbul with the full knowledge of the Consul General himself.”
The non-resident fellow at the Brookings Doha Centre went on to assert the very airline that had flown the men involved in the murder into Turkey had ties to Mohammad bin Salman – therefore directly implicating the Saudi ruler in the killing.
He said: “Now it is established that the jet company that flew these people into Turkey has very close connections to MBS himself.
“It could not have happened without the knowledge of the Crown Prince.”
Mr Khashoggi was last seen entering the Saudi consulate in Istanbul on October 2, leaving his fiancée behind as he went in to collect documents confirming his divorce.
In response to the murder, US President Donald Trump announced yesterday he would revoke the visas of 21 Saudi officials.
The President said the cover-up of Mr Khashoggi’s killing was “one of the worst cover-ups in history” and a “total fiasco”.
He said: “There should have never been an execution or a cover-up because it should have never happened.
“I would say it was a total fiasco from day one.”
Meanwhile, in an ominous warning, US Vice President Mike Pence vowed the Khashoggi murder would “not go without an American response”.
The US interventions came just hours after Turkish leader Recep Tayyip Erdoğan dubbed the crime as “savage” in an explosive public address in which he demanded to know where Mr Khashoggi’s body had been hidden.
Turkish officials have been scouring rural areas surrounding Istanbul – including Belgrad forest – for traces of Mr Khashoggi’s remains, which have since been discovered in the garden of the Saudi Consul General in Istanbul, according to reports.