The fiancée of slain journalist Jamal Khashoggi took her campaign for justice in his killing to the United Nations' top human rights body Tuesday and urged the UN to take "the next step" following a key investigator's finding that Saudi Arabia bears responsibility.

Hatice Cengiz, a Turkish citizen, told a Human Rights Council event in Geneva about her grief over Khashoggi's Oct. 2 slaying at the Saudi Consulate in Istanbul when he went there to pick up a document for their marriage.

Cengiz said the possibility her fiancé might not really be dead haunts her because his body hasn't been found, compounding her loss with "an unbelievably different kind of trauma."

She appeared at a 90-minute council "side event" organized by Canada and hosted by advocacy group No Peace Without Justice. Cengiz provided one of several testimonials on the theme "Silencing Dissent."

In her testimony on Khashoggi's killing, Cengiz cited many of independent UN expert Agnes Callamard's findings, which were released last week in a 101-page report.

Callamard, a fellow panellist, laid out an excruciatingly detailed account of the Washington Post columnist's alleged final moments at the consulate. She said more investigation was warranted of Saudi crown prince Mohammed bin Salman's possible role in Khashoggi's killing.

Callamard said last week that countries should invoke universal jurisdiction to further bring the perpetrators to justice. Judicial authorities in countries that recognize universal jurisdiction for serious offences such as war crimes and torture can investigate and prosecute those crimes no matter where they were committed.

Speaking through a translator, Cengiz said the report needed to be acted upon and noted the crown prince may one day be Saudi Arabia's head of state.

"The report points to the fact that important Saudi officials, big officials, may have been involved," she said. "It says this should be pursued and it says that an international murder investigation should be opened."

Region a 'vicious, hostile place': Trump

Cengiz said the "international public" needs to exert pressure to ensure the case isn't forgotten "and the United Nations needs to take this to the next step."

Cengiz said in a subsequent interview with The Associated Press that she wants U.S. President Donald Trump and other world leaders to press the issue at the G20 summit in Osaka, Japan, where the crown prince is on the guest list.

"Saudi Arabia needs to take steps in order for us to find out the truth about this incident. They have to be punished in some way," Cengiz said. "This incident cannot remain unanswered."

During her comments at Tuesday's panel, Callamard, an academic and longtime human rights advocate, took up broader themes. She decried a trend of violence against journalists and others who speak truth to power.

"The targeted killings of journalists, human rights defenders, dissenters more generally, is on the increase," she said. "The most worrying pattern is that impunity for those killings and the continuation of those killings [has] not gone down."

Already this year, more than 40 journalists have died doing their job. Author and Washington Post columnist Anne Applebaum says there will be more because the global reach of what journalists are writing and broadcasting is putting them in conflict with the people they are trying to hold to account like never before. Watch ‘The Investigators with Diana Swain’ Thursdays at 7:00 pm on CBC Television; Saturdays at 9:30 pm ET and Sundays at 5:30 pm ET on CBC News Network. 4:03

Saudi Arabia is among the 47 member states of the Human Rights Council, which opened its three-week summer session Monday. Callamard was expected to present her report formally to the council on Wednesday, and the Saudi delegation is entitled to give a reply.

Khashoggi was a U.S. resident with children who are American citizens, but the White House has shown little appetite for pressing the matter of this death further.

"I think it's been heavily investigated," Trump told NBC News in an interview broadcast on Sunday.

Trump and other officials have continually stressed the U.S. economic and military partnership with the Saudis as a bulwark against what they see as Iranian aggression in the region.

"Iran's killed many, many people a day. Other countries in the Middle East, this is a hostile place. This is a vicious, hostile place," said Trump. "If you're going to look at Saudi Arabia, look at Iran, look at other countries."

Trump told NBC's Meet the Press in the same interview that the subject of Khashoggi "didn't come up" when he and Mohammed bin Salman spoke on June 20, the day after the report was released. The State Department also said Khashoggi's killing was not part of the discussion when U.S. Secretary of State Mike Pompeo met with Saudi King Salman bin Abdulaziz Al Saud on Monday.

Most of the speakers criticized alleged rights abuses in Saudi Arabia and the United Arab Emirates. Diplomats from Western nations and regional countries like Turkey and Qatar were in the audience.