Vigil for Khashoggi at Saudi Consulate in Istanbul
ISTANBUL, TURKEY - OCTOBER 25: People take part in a candle light vigil to remember journalist Jamal Khashoggi outside the Saudi Arabia consulate on October 25, 2018 in Istanbul, Turkey. Jamal Khashoggi, a U.S. resident and critic of the Saudi regime, went missing after entering the Saudi Arabian consulate in Istanbul on October 2. More than two weeks later Riyadh announced he had been killed accidentally during an altercation with Saudi consulate officials, however as investigations continue new information surfaced, pointing to a brutal and planned murder contradicting previous claims.Chris McGrath/Getty Images [Representational Image]

The United Nation's (UN) special rapporteur cited credible information in her report on Wednesday, June 19, stating that the crown prince of Saudi Arabia Mohammed bin Salman should be investigated over the murder of slain journalist Jamal Khashoggi.

Agnes Callamard, UN investigator on extra-judicial executions, in her report said that Saudi Arabia is responsible for the murder of Khashoggi, who was killed by the Saudi agents inside the Saudi consulate in Istanbul, Turkey. The report said that further investigation should be conducted over Khashoggi's death as several top-level Saudi officials including the crown prince have a play in it.

In her report, the UN investigator said that the evidence collected during her investigation shows that "prima facie case that Mr Khashoggi was the victim of a brutal and premeditated killing, planned and perpetrated by officials of the state of Saudi Arabia".

Callamard said that she could not find the remains of Khashoggi but she and her team of forensic and legal experts had access to a part of "chilling and gruesome audio materials" of his death obtained by the Turkish intelligence agency.

The report stressed that "no conclusion is made as to guilt. The only conclusion made is that there is credible evidence meriting further investigation, by a proper authority, as to whether the threshold of criminal responsibility has been met," reports AFP.

She urged the Secretary-General of UN, Antonio Guterres to launch an official international criminal investigation into the case, which she said would make it possible to "build-up strong files on each of the alleged perpetrators and identify mechanisms for formal accountability, such as an ad hoc or hybrid tribunal," adds the report.

Callamard's report said that the probes conducted by investigators of Saudi Arabia and Turkey so far had failed to meet international standards, regarding the investigation into unlawful deaths.