A trial in the killing of Saudi journalist Jamal Khashoggi opened Friday in a Turkish court, though none of the 20 defendants charged in the killing, all nationals of Saudi Arabia, were in attendance.

Turkey’s trial is the first public legal inquiry into Khashoggi’s death at the hands of Saudi agents in Istanbul, a killing that sparked global outrage and focused attention on Saudi Crown Prince Mohammed bin Salman’s pursuit of his critics. Saudi Arabia held its own trial, behind closed doors. Saudi officials have refused Turkey’s request to extradite the suspects in the 2018 slaying.

“The Saudi process was anything but justice. It was a travesty of justice in my opinion,” Agnès Callamard, a United Nations human rights expert who conducted a separate investigation into the killing, told reporters Friday after the hearing in Istanbul.

The Turkish trial, despite its many limitations, is still an “important judicial process,” she said. “Here we have a space where the victims are heard in a way they have never been heard before. We have a space where witnesses are asked to speak under oath.”

Khashoggi was killed in the Saudi Consulate in Istanbul in October 2018 by a team of Saudi government agents who were sent to Turkey from Riyadh, the Saudi capital, to confront the journalist. At the time of his death, Khashoggi, who contributed columns to The Washington Post, was a prominent critic of the crown prince, the kingdom’s day-to-day ruler.

Khashoggi went to the consulate to collect documents that would allow him to remarry and was killed while his fiancee, Hatice Cengiz, waited for him outside.

Turkish President Recep Tay­yip Erdogan’s government quickly publicized details of the Saudi plot, sparking a rift with the kingdom’s leadership that has continued to the present. The CIA concluded with “medium to high confidence” that Mohammed had ordered the killing, a conclusion the crown prince has denied. Saudi officials have portrayed the slaying as the work of rogue operatives.

The Saudi public prosecutor announced in December that five suspects had been sentenced to death in Khashoggi’s killing, after a trial that lasted nearly a year. The prosecutor did not identify the suspects.

In March, Turkish prosecutors indicted 20 people on murder charges, including two senior Saudi officials: Saud al-Qahtani, a close adviser to Mohammed, and Ahmed al-Assiri, a former deputy head of Saudi intelligence. The two officials, who were earlier cleared of wrongdoing by the Saudi court, were charged in Turkey with having “instigated premeditated murder with monstrous intent.”

On Friday, the Saudi defendants were represented by more than a dozen court-appointed lawyers, who said they had been unable to reach their clients.

The trial in Turkey could shed light on some of the many unanswered questions in the case, including the location of Khashoggi’s remains. The Saudi agents dismembered his body after killing the journalist, according to Saudi and Turkish prosecutors.

Witnesses who testified in the hearing included Turkish citizens who worked at the Saudi Consulate or at the nearby residence of the Saudi consul general, Mohammed al-Otaibi. One of the witnesses, Zeki Demir, a handyman, testified that he was asked to light a wood-burning oven at the residence. Investigators had earlier speculated that Khashoggi’s remains may have been disposed of in the stove.

Another employee, Emrullah Oz, a driver, said he and other employees were told not to come to the residence on Oct. 2, the day Khashoggi was killed, because the house was being renovated.

Cengiz, who testified during the court hearing, called the process of pursuing her fiance’s killers “both spiritually and psychologically very tiring,” in brief comments to reporters after the hearing.

“We will continue seeking justice not just in Turkey but everywhere we can,” she said.

Zeynep Karatas in Istanbul contributed to this report.