By Laura Smith-Spark and Hamdi Alkhshali, CNN

(CNN) -- The killing of the Saudi journalist Jamal Khashoggi in Saudi Arabia's Istanbul consulate was premeditated, the country's attorney general said Thursday, in what marks a further significant shift in the Saudi version of events.

According to a statement posted by the Saudi state news agency, the latest evolution in the official Saudi narrative around Khashoggi's death came after new information was received from Turkish investigators.

"The public prosecution received information from the Turkish side through the Joint Working Group between the Kingdom of Saudi Arabia and the Turkish Republic, indicating that the suspects in Khashoggi's case premeditated their crime," Attorney General Shaikh Suood bin Abdullah Al Mo'jab said.

"The public prosecution continues its investigations with the accused in accordance with the latest investigation results to reach the facts, God willing, and complete the course of justice."

The development comes as CIA director Gina Haspel is set to brief US President Donald Trump on the investigation into Khashoggi's death.

Haspel traveled to Turkey on Monday, apparently to assess information the Turks have collected on Khashoggi's killing inside the Saudi Consulate in Istanbul. The Washington Post reported Wednesday that Haspel listened to audio purportedly of his interrogation and murder while she was in Turkey. Trump also said the US has sent officials to Saudi Arabia to get more information on the killing, which has spiraled into a crisis.

Turkish investigators continue to hunt for clues to the whereabouts of Khashoggi's body.

Meanwhile, Khashoggi's eldest son has left Saudi Arabia, a source close to the family told CNN. Salah bin Jamal Khashoggi is a dual US-Saudi citizen and had been unable to leave Saudi Arabia after his passport was restricted by the kingdom some months ago.

News of his departure came two days after he was pictured shaking hands with Saudi Crown Prince Mohammed bin Salman and his father, King Salman, in Riyadh.

Saudi minister: Khashoggi's death 'a murder'

Saudi Arabia initially maintained that Khashoggi, who had been writing critical columns in The Washington Post, had left the consulate alive on October 2. Then, in a public admission Saturday, Saudi Arabia claimed that Khashoggi died when a discussion turned violent.

In private, officials have offered a changing narrative. In a version offered by an official on Tuesday, the original plan was to persuade Khashoggi to return to Saudi Arabia, and if he refused, to drug him and take him to a safe house in Istanbul. But Khashoggi became agitated, the official asserted, and he died in a chokehold.

Riyadh has maintained that neither bin Salman nor King Salman knew of the operation to target Khashoggi. US officials have said such a mission -- including 15 men sent from Riyadh -- could not have been carried out without the authorization of bin Salman, the country's de facto ruler.

After Saudi Arabia admitted over the weekend that Khashoggi was killed October 2 in its Istanbul consulate, five high-ranking officials were dismissed, including bin Salman's media chief and the deputy head of the Saudi intelligence service. Eighteen people were arrested.

It also announced steps to restructure the kingdom's intelligence services. Bin Salman has chaired the first meeting of a committee set up for that purpose, the state-run Saudi Press Agency reported Thursday.

In his first comments since some of his closest aides were implicated in Khashoggi's death, the Crown Prince on Wednesday described the killing as a "heinous" crime and vowed to bring those responsible to justice.

Later that day, Saudi Energy Minister Khalid Al Falih admitted the scandal of Khashoggi's killing was a blow to the kingdom.

"It's not a death, it's a murder. We admit it, we're dealing with it. As such, we will be transparent and show our allies and friends in the United States ... that the kingdom is as unhappy about what has happened as anybody else. In fact, we are more unhappy because it has tarnished the name of the kingdom," he said, speaking to CNN on the sidelines of a high-profile investment conference in Riyadh.

However, he added that Saudi Arabia would emerge from the crisis stronger.

The Saudi government has faced wide condemnation from western nations over Khashoggi's killing and its apparent cover-up. Many international business leaders pulled out of the Future Investment Initiative conference in Riyadh amid the furor.

As the diplomatic backlash continues, members of the European Parliament voted overwhelmingly Thursday to adopt a resolution that urges EU countries to impose an EU-wide arms embargo on Saudi Arabia.

The lawmakers also "condemn in the strongest possible terms the torture and killing" of Khashoggi and call for "an impartial, international investigation into his death."

Turkey 'taking all necessary steps'

Turkey has rejected the notion that Khashoggi fell victim to a rogue operation.

Turkish Foreign Minister Mevlüt Çavuşoğlu said Thursday that while Turkey did not intend to initiate an investigation by an international court, it would share information if one was launched.

"We're not intending to take this to the international courts. However, if the international courts take the initiative and launch an investigation, of course we will share the information, evidence and investigation results we have, as a matter of fact we're obligated to," he said, speaking at a joint news conference with his Palestinian counterpart Riyad al-Maliki in Ankara.

"Ankara is taking all necessary steps to clear up the case of slain Saudi journalist Jamal Khashoggi," he added. "Everyone connected to the murder of the Saudi journalist needs to be investigated, tried in Turkey."

Turkish President Recep Tayyip Erdogan described the death Tuesday as a "ferocious" premeditated murder. A day later, he once again made clear he was not satisfied with the Saudi explanation.

"We are determined not to allow those responsible -- those who ordered the crime and those who committed it -- to escape justice," he said.