An independent U.N. human rights expert investigating the killing of Saudi journalist Jamal Khashoggi is recommending an investigation into the possible role of Saudi Crown Prince Mohammed bin Salman, citing "credible evidence." The investigator stopped short of blaming bin Salman directly for the murder, but said the state of Saudi Arabia was responsible.

Investigator Agnes Callamard released a 101-page report into the October 2 killing of Khashoggi at the Saudi consulate in Istanbul that lays out dozens of recommendations. It calls on U.N. bodies or Secretary-General Antonio Guterres to "demand" a follow-up criminal investigation.

Callamard the U.N. special rapporteur on extrajudicial, summary or arbitrary executions, noted the "extreme sensitivity" of considering the criminal responsibility of bin Salman, as well as Saud Alqahtani, a senior adviser to the Saudi royal court who has also not been charged.

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Credible evidence

"No conclusion is made as to guilt," she wrote of the two men. "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."

According to the report, Callamard "understands the extreme sensitivity of considering the criminal responsibility of a person who, in conjunction with his father, the King, is running the operations of the State of Saudi Arabia. Academic research on Saudi Arabia tends to suggest that the level of control exerted by the Crown Prince over the management of the country's political, security and economic affairs is extremely high."

The CIA has concluded that bin Salman very likely ordered the murder himself, based in part on the same understanding of his power over all actions taken by the Saudi security apparatus which Callamard referenced.

"Evidence points to the 15-person mission to execute Mr. Khashoggi requiring significant government coordination, resources and finances," Callamard's report states. "While the Saudi government claims that these resources were put in place by Ahmed Asiri (a senior aid to the bin Salman who has been accused by the Saudi government), every expert consulted finds it inconceivable that an operation of this scale could be implemented without the Crown Prince being aware, at a minimum, that some sort of mission of a criminal nature, directed at Mr. Khashoggi, was being launched."

The Trump administration, however, has fostered the longstanding, deep U.S. ties with Saudi Arabia and refused to pin the blame for the killing on bin Salman or any other member of the royal family thus far. Mr. Trump himself has cast doubt on the assessment of his own intelligence agencies on the matter.

Khashoggi, a Washington Post columnist who wrote critically about bin Salman, was killed and dismembered inside the Saudi Consulate in Istanbul last October. His remains have not been found. The brutal killing -- described by Callamard and Turkish and U.S. officials as an elaborate plot -- drew an international outcry about press freedom and Saudi government tactics to quell criticism.

The murder came amid a crackdown by Crown Prince bin Salman on democracy advocates, journalists and perceived dissidents in Saudi Arabia -- some of whom were allegedly executed or jailed without charge. Callamard said in her report that the heir to the throne undeniable bore some degree of responsibility for the journalists' murder simply for allowing that crackdown to continue.

"At a bare minimum, Crown Prince condoned this behavior and allowed the repetition and escalation of these crimes. He took no action to prevent or punish those responsible. The Crown Prince willingly took the risk that other crimes, such as the killing of Mr. Khashoggi, would be committed, whether or not he directly ordered the specific crime," she said.

Saudi's secret trials

Saudi Arabia quietly held a second court hearing early this year for 11 people facing charges in the country over the Khashoggi killing. At the time Callamard criticized the kingdom for its lack of transparency in the proceedings over the grisly slaying. She said she learned of the hearing during her first visit to Turkey to investigate the murder.

After denying for weeks that Khashoggi was killed in the consulate, Saudi Arabia late last year indicted 11 people in the killing, including members from the crown prince's entourage, and is was seeking the death penalty against five of them.

Callamard told The Associated Press in February that the second hearing in Saudi Arabia took place on Jan. 31. She criticized the fact that there was "insufficient public attention placed on the proceedings" and that media were not present at the hearings.

Trials in Saudi Arabia can be shrouded in secrecy, she noted, insisting that Khashoggi case should be open to public scrutiny.

"Given the importance of the case, we should be expecting a greater presence of representatives of the media, of civil society, of a range of other governments, not just those hand-picked by the Saudi authorities," said Callamard, a French national who is also director of Columbia Global Freedom of Expression at Columbia University in New York.