The 59-year-old Washington Post columnist was killed by Saudi agents inside the consulate when he went there to collect paperwork required for his planned marriage.
He was personally known to and respected by President Recep Tayyip Erdogan and Ankara believed the Saudi “hit squad” who travelled to the country to carry out the killing had breached Turkey’s sovereignty.
The gruesome murder, details of which Turkish officials shared with domestic and international media as well as with foreign governments, placed a further strain on the relationship between Riyadh and Ankara.
Khashoggi was first reported missing by Hatice Cengiz, his Turkish fiancee, on October 2, but Saudi authorities issued a statement the following day saying he had left the consulate soon after he entered the premises, a claim Turkish authorities contradicted at the time.
Days later, a government official said Turkish police had concluded from an initial investigation that the journalist had been killed inside the building.
On October 20, following weeks of denials of involvement with the journalist’s disappearance, Riyadh admitted that Khashoggi had been killed as part of a premeditated plan, but said it was carried out by rogue operators without the knowledge of the government.
The Turkish authorities say his body was dismembered, removed from the building, and that its whereabouts are unknown.
In the weeks following the murder, Ankara shared information, including audio recordings and visuals, with domestic and international media, as well as with foreign governments, including the United States, according to Turkish officials.
Ankara also demanded international support to pressure Saudi Arabia to extradite the accused operatives to Turkey, as the crime was committed in Turkish territory.
“Turkey approached the murder in a humanitarian manner since day one, demanding international pressure to bring the ones responsible to justice, including the ones who ordered the murder,” Yasin Aktay, a presidential adviser and friend of Khashoggi’s, told Al Jazeera.
“Any country whose sovereignty was breached in such a case would act in the same manner. A state is responsible for the security of people within its borders. And we shared all the information we have with the world,” he added.
Eleven suspects have been put on trial in Saudi Arabia, according to Riyadh, although no more details about the process were revealed. Saudi reports say prosecutors in the kingdom are seeking the death penalty for five of the suspects.
Meanwhile, Turkish prosecutors started their own investigation last year and have been gathering evidence to open a case to try the suspects in absentia over the journalist’s murder.
In March, Turkey announced that Interpol had issued red notices for 20 people in relation to the killing, asking police worldwide to locate and provisionally arrest them pending extradition.
“The legal process in Saudi Arabia cannot be healthy or bear any fruit. This is because, most of all other reasons, the incident happened by the hand of the Saudi state, and evidence shows that the order came from the top of the state,” Aktay said.
“The Saudi bureaucracy has a very rigid hierarchical structure, and such an organised killing cannot be committed without the knowledge of the top authorities in the country. And the judiciary there cannot be impartial in such a case.”
Aktay also said that, during the trials that are soon to start in Turkey, prosecutors will publicise all the evidence they gathered once again so the world knows the details of the case.
He added that the unconditional support the administration of US President Donald Trump showed Saudi Arabia made it hard to pressure Riyadh to bring Khashoggi’s killers to justice.
A CIA investigation last year reportedly concluded that Saudi Crown Prince Mohammed bin Salman ordered the assassination of the journalist – an assessment publicly disputed by Trump.
Ankara and Riyadh have a historical rivalry in the Middle East and in recent years have found themselves on opposite sides of various regional issues, such as the 2013 coup in Egypt and the ongoing GCC crisis.
In Egypt, Ankara supported Mohamed Morsi, the country’s first democratically elected leader who took office in 2012, while Saudi Arabia backed his overthrow in a 2013 coup led by current President Abdel Fattah el-Sisi.
Furthermore, the two counties took opposite sides over the blockade of Qatar by a group of Arab states led by Saudi Arabia, which has been ongoing since June 2017.
They also have differing positions on the Syrian civil war and the US’s “maximum pressure” campaign on Iran.
Their wildly differing responses to Khashoggi’s killing added another conflict to the soured relations between the two regional powers.
One of the most recent examples is Saudi Foreign Minister Ibrahim bin Abdulaziz Al-Assaf’s remarks during a recent visit to Cyprus, where he was quoted voicing support for the country in its dispute with Turkey, a new stance by the Saudi government.
Cyprus has been divided since Turkish troops occupied its northern third in 1974, following a Greek Cypriot coup sponsored by the military government in Greece. The two Mediterranean countries have also been at odds on exploration and exploitation of gas reserves around the Mediterranean island.
Meanwhile, Erdogan, in comments during the UN General Assembly in New York last week, voiced support for Iran, which Washington and Riyadh blame for the recent attacks on key Saudi oil facilities. The Turkish president has also criticised a Saudi-led coalition’s war in Yemen.
According to Aktay, the two sides should handle the Khashoggi case separately from other regional matters.
“Saudi leadership perceives being vocal about the Khashoggi case as an attack on their country. Turkey would act in the same manner to any country that would commit the same crime within its borders,” Aktay told Al Jazeera.