Saudi Arabia’s obscure judiciary, led by a prosecutor known above all for his fealty to the country’s powerful Crown Prince, claims it has sentenced five men to death for the kidnap, torture, murder and dismemberment of journalist Jamal Khashoggi.

Three others have been given jail terms totalling 24 years in relation to the murder of the Washington Post journalist at the Saudi consulate in Istanbul in 2018.

In a rare public statement about the case, a Saudi official said Khashoggi’s killers decided to murder the writer after their arrival in Istanbul.

“Our investigations show that there was no premeditation to kill at the beginning of the mission,” Shaalan al-Shaalan, a spokesman for the prosecutor, said in a press conference broadcast by Saudi regime mouthpiece al-Arabiya TV.

“The killing was in the spur of the moment, when the head of the negotiating team inspected the premises of the consulate and realised that it was impossible to move the victim to a safe place to resume interrogations, to resume negotiations. The head of the negotiating team and the perpetrators then discussed and agreed to kill the victim inside the consulate.”

Jamal Khashoggi death: key figures Show all 7 1 /7 Jamal Khashoggi death: key figures Jamal Khashoggi death: key figures Jamal Khashoggi Washington Post journalist who was critical of the Saudi regime and the young Crown Prince Mohammed bin Salman, he was murdered on 2 October in the Saudi Arabian consulate in Istanbul AFP Jamal Khashoggi death: key figures Saudi Crown Prince Mohammed bin Salman Heir to the Saudi throne, Mohammed bin Salman has been implicated in the murder, with US officials claiming that he must have known of the plot AFP/Getty Jamal Khashoggi death: key figures 15 man hit squad Turkish police suspect these 15 men of being involved in the murder of Jamal Khashoggi, issued 10 October, 8 days after the journalist disappeared EPA Jamal Khashoggi death: key figures Saud al-Qahtani Aide to Crown Prince Mohammed bin Salman, Saud al-Qahtani is claimed to have ordered Khashoggi's murder Saud Al-Qahtani/Twitter Jamal Khashoggi death: key figures Maher Abdulaziz Mutreb A former diplomat who often travelled with the Crown Prince, Mutreb was initially claimed to be the leader of the hit squad and is pictured here entering the Saudi consulate on the day of the murder AP Jamal Khashoggi death: key figures Mustafa al-Madani First implicated in the 15 CCTV photos released by the Turkish police, al-Madani was later found to have been used as a body double for Khashoggi, leaving the Saudi consulate dressed in his clothes on the day the journalist was killed CNN Jamal Khashoggi death: key figures Salah bin Jamal Khashoggi (L) Son of the murdered journalist met with Crown Prince Mohammed bin Salman on 23 October EPA

Citing Saudi law, none of those convicted has yet been named, even though dissidents accused of national security offences are regularly named and smeared in Saudi media outlets. Under Saudi law, death sentences must be confirmed in appeal and upheld by a high court.

At least 10 officials, including two top-ranking officials involved in the killing of the 59-year-old Washington resident, were exonerated.

The public prosecutor’s office said Saud al-Qahtani, a high-profile Saudi royal adviser to Crown Prince Mohammed bin Salman, was investigated but released without charges.

The former deputy intelligence chief Ahmed Al-Asiri was also released by the Saudi authorities for “insufficient evidence”.

In Turkey, Yasin Aktay, a member of Turkey’s ruling party and a friend of Khashoggi, criticised the verdict, saying the Saudi court had failed to bring the real perpetrators to justice.

“The prosecutor sentenced five hitmen to death but did not touch those who were behind the five,” Aktay said.

Khashoggi’s son, Salah, wrote on Twitter that the family had “full confidence” in the Saudi judiciary.

The killing of Khashoggi, a critic of Prince Mohammed, caused a global uproar, though it ultimately failed to prevent western powers from selling Saudi Arabia advanced weapons and surveillance systems. Many of the global corporations that shunned oil-rich Saudi in the wake of the killing are already crawling back to the kingdom, looking for deals.

Saudi Arabia initially claimed it knew nothing about Khashoggi’s disappearance after he entered the consulate building to obtain some paperwork, but eventually admitted under a torrent of leaked surveillance footage and travel documents that a death squad close to the Crown Prince had flown to Istanbul to capture and murder the writer in what it claimed was an unauthorised rogue operation.

To date, there has been no full accounting of the chain of command by which some two dozen trained enforcers, a forensic pathologist and a body double dressed up to resemble Khashoggi, as well as subsequent clean-up teams, were dispatched from Riyadh to Istanbul.

Human rights advocates have condemned the trial of Khashoggi’s killers, which has been witnessed by only a handful of diplomats sworn to secrecy. Nine sessions of the trial were reportedly held. Agnes Callamard, the UN rapporteur investigating the killing, has yet to be be granted permission to visit Saudi Arabia.

In a series of tweets, Ms Callamard condemned the ruling as a “travesty”, noting that at no point did the trial even consider the involvement of the state.