5 Saudis sentenced to death for roles in killing Washington Post columnist Jamal Khashoggi The sentences were announced by the Saudi public prosecutor on Monday.

LONDON -- Five men have been sentenced to death for their roles in the killing of former Washington Post columnist Jamal Khashogghi, Saudi Arabia's public prosecutor announced Monday.

Khashogghi, a dissident who had U.S. residency, was killed by Saudi agents inside the kingdom's consulate in Istanbul last year.

His killing has roiled U.S.-Saudi relations despite efforts by President Donald Trump and his top allies to defend the relationship -- with lawmakers in both parties calling for more pressure on Crown Prince Mohammed bin Salman, the kingdom's de facto ruler. A senior State Department official called the sentences an "important step" on Monday.

The five unnamed individuals have been sentenced to death for "committing and directly participating in the murder of the victim," according to the Saudi public prosecutor. In addition, three people were sentenced to a total of 24 years in prison.

The court also found three individuals not guilty of involvement in the murder.

The Saudi investigation and trial relating to the murder of Khashogghi have been shrouded in secrecy. None of the evidence disclosed to the Saudi courts has been made public.

Despite that, the Trump administration did not directly criticize the proceedings.

"We've said all along that we felt that this process was necessarily imperfect, but we're pressing them for more transparency and for holding everybody accountable," the senior State Department official told reporters.

A U.N. report from June accused the highest levels of the Saudi leadership, including the crown prince, of being directly responsible for the murder. Bin Salman has denied direct responsibility in the past and said the killing was a rogue operation.

Saudi Arabia blasted the report as based on "many unfounded accusations" and questioned "the impartiality and lack of objectivity of the report" and its author, U.N. Special Rapporteur on extrajudicial, summary or arbitrary executions Agnès Callamard.

On Monday, Callamard criticized all aspects of the trial in a string of tweets.

"Bottom line: the hit-men are guilty, sentenced to death," she wrote. "The masterminds not only walk free. They have barely been touched by the investigation and the trial. That is the antithesis of Justice. It is a mockery."

But the senior State Department official would not discuss the U.S. assessment of the crown prince's culpability.

"I know that there are some who would say that this hasn't touched everybody responsible in the kingdom. We will continue to encourage transparency in that regard," the official added -- saying the Trump administration had done so by sanctioning and issuing visa bans for 17 Saudi officials.

Khashogghi lived in the U.S. in exile, where he penned several articles critical of the Saudi regime, and particularly the reform agenda of the crown prince, sometimes known by his initials, "MBS."

Fred Ryan, the publisher of The Washington Post, decried the public prosecutor's announcement, describing the judicial process as a "sham trial."

"The complete lack of transparency and the Saudi government's refusal to cooperate with independent investigators suggests that this was merely a sham trial," he said in a statement. "Those ultimately responsible, at the highest level of the Saudi government, continue to escape responsibility for the brutal murder of Jamal Khashoggi."

The journalist first visited the Saudi consulate in Istanbul to secure documents to marry his fiancée, Hatice Cengiz, on Sept. 28, 2018. He was told to come back later and returned to the consulate on Oct. 2. He was never seen again and his remains are yet to be found.

Transcripts leaked by Turkish officials in September and confirmed by ABC News, revealed new details from the murder that has sparked both international condemnation and intrigue. The recorded conversations from before Khashoggi arrived at the consulate involved a 15-member team of Saudi officials discussing what to do with his body, as well as the journalist's final conversations with his killers.

It is still not clear how the Turkish government was able to record the events as they unfolded.

Saudi Arabia has denied that high-level officials were involved in sanctioning the murder, saying that the team was rogue, misinterpreting an old edict to convince Saudi dissidents to come home and killing Khashoggi by accident.

Cengiz told ABC News last year that Khashoggi feared entering the Saudi consulate because of his "political views."

"He did not want to go to the consulate," Cengiz said. "He thought it was a risk to go. He thought of the possibility of them capturing him. He didn't want to face the consequences of his political views."

President Donald Trump and his administration, which enjoys a close relationship with bin Salman, has been largely dismissive of Saudi leadership being involved in the murder of Khashoggi. Days after the release of the U.N. report, Secretary of State Mike Pompeo did not raise the issue with bin Salman or the Saudi king in a visit to the country, and Trump praised the countries' economic relationship and called Saudi Arabia a "vicious, hostile place" no different than many other countries that could be investigated.