ISTANBUL — Saudi Crown Prince Mohammed bin Salman called the son of Jamal Khashoggi, the kingdom announced early Monday, to express condolences for the death of the journalist killed at the Saudi Consulate in Istanbul by officials that allegedly included at least one member of the royal's own entourage. The senior royal's call was made as new evidence leaked to the media appeared to bolster allegations that Prince Salman's own confidants killed Khashoggi and then went to considerable lengths to try and cover it up.

King Salman similarly made a condolence call as international pressure on the kingdom continues to rise, even after it acknowledged Saturday that the Washington Post journalist was killed Oct. 2 at the consulate under still-disputed circumstances.

The state-run Saudi Press Agency announced the calls to Khashoggi's son, Salah, early Monday morning. Statements from the agency said both King Salman and Prince Mohammed express their condolences for his father's death.

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A Saudi friend of Khashoggi who was in frequent touch with him before his death told The Associated Press that Khashoggi's son, Salah, has been under a travel ban and barred from leaving the kingdom since last year as a result of his father's criticism of the government. The friend spoke on condition of anonymity for fear of repercussion. The Saudi statements did not acknowledge the ban.

The calls comes after a leaked photograph apparently taken from surveillance footage shows Maher Abdulaziz Mutreb, a member of Prince Mohammed's entourage on trips to the United States, France and Spain this year, at the consulate, just ahead of Khashoggi's arrival.

Saudi Arabia so far has not acknowledged or explained Mutreb's presence in Istanbul -- nor that of a forensics and autopsy expert, also on hand for Khashoggi's arrival at the consulate.

New leaks bolster claims of a cover-up

Meanwhile, a Turkish newspaper with close ties to Turkey's leader, Yeni Safak, claimed Monday that Mutreb had called the crown prince's personal secretary four times on his cell phone from the Saudi Consul General's office in Istanbul immediately after Khashoggi was killed.

Also Monday, CNN broadcast images which appeared to bolster the claims of a botched cover-up by the Saudi operatives who ended up killing Khashoggi. Saudi officials, speaking anonymously over the weekend, told the Reuters news agency a member of the Saudi entourage dressed himself as Khashoggi and walked out a consulate back door on the day the journalist was killed, hoping to lend credence to the kingdom's initial claim the journalist left unharmed.

The images obtained by CNN show a man, identified by Turkish officials to CNN as Saudi operative Mustafa al-Madani, appearing to be in Khashoggi's own clothing, walking out a consulate back door Oct. 2. CNN said that, according to Turkish officials, al-Madani was chosen from among the alleged "hit-squad" as a body double for Khashoggi as both men were of roughly the same age and physical appearance.

Later Monday, Turkish officials said a vehicle registered to the Saudi consulate in Istanbul had been discovered parked in another part of the city, and it would be searched by police.

Turkey's evidence "will be revealed"

Turkish President Recep Tayyip Erdogan has said details of Khashoggi's killing "will be revealed in all its nakedness" in a speech in parliament on Tuesday, the same day a glitzy investment forum in Riyadh spearheaded by Prince Mohammed is to take place.

Saudi Arabia's explanation Khashoggi was killed in a "fistfight" and 18 Saudis have been detained has been met with international skepticism and allegations of a cover-up designed to absolve Prince Mohammed of direct responsibility. Turkish media reports and officials say a 15-member Saudi team flew to Istanbul, laid in wait for Khashoggi at the consulate and then cut off his fingers, killed and dismembered the 59-year-old writer.

"Why did these 15 people come here? Why were 18 people arrested? All of this needs to be explained in all its details," Erdogan said.

U.S. officials have been piling increasing pressure on Turkey to share purportedly damning evidence it has that Khashoggi was in fact brutally murdered. Specifically, anonymous Turkish officials have been touting an alleged audio recording of the killing to journalists since soon after Khashoggi vanished, but there has been no proof thus far any such audio even exists.

Istanbul's chief prosecutor summoned 28 more staff members of the Saudi Consulate, including Turkish citizens and foreign nationals, to give testimony on Monday, Turkish state broadcaster TRT reported. Prosecutors have previously questioned consulate staff; some Turkish employees reportedly said they were instructed not to go to work around the time Khashoggi disappeared.

Turkish news agency Anadolu Agency reported Sunday that Khashoggi's fiancée, Hatice Cengiz, has been given 24-hour police protection.

Also Sunday, images that were obtained by TRT World, a Turkish news channel that broadcasts in English, showed Khashoggi as he arrived at a police barrier before entering the consulate on Oct. 2. The images, taken from security camera video, show the writer being searched before continuing toward the building.

Congress and Trump react to "rogue operation" claim

­­­Saudi Foreign Minister Adel al-Jubeir said on Fox News that Khashoggi's killing was "a rogue operation" and "we don't know where the body is.'"

"The individuals who did this did this outside the scope of their authority," he said. "There obviously was a tremendous mistake made and what compounded the mistake­ was the attempt to try to cover up. That is unacceptable to the government."

CBS News chief White House correspondent Major Garrett says President Trump has appeared thus far willing to believe the Saudis' assertions it wasn't murder, the crown prince himself knew nothing and the Saudis can conduct a credible investigation into a death they have been forced to admit came at their hands.

However, a leading U.S. Senate Republican said the Saudi explanation, which followed initial denials from the kingdom that it knew anything about Khashoggi's fate, wasn't credible.

Bob Corker, chairman of the Senate Foreign Relations Committee, said Saturday on CNN's "State of the Union" that he believed Prince Mohammed, the heir-apparent of the world's largest oil exporter, was behind the killing.

The crown prince has "now crossed a line and there has to be a punishment and a price paid for that," Corker said. He also urged Turkey to turn over the purported audio recordings of Khashoggi's killing inside the Saudi Consulate in Istanbul. The existence of such evidence has been reported in Turkish media in a series of leaks, though Turkish officials have yet to confirm they have recordings.

"The Turks have been talking more to the media than they have (to) us," Corker said of the NATO ally.

California Rep. Adam Schiff, the top Democrat on the House intelligence committee, said on ABC's "This Week" the killing should be a "relationship-altering" event for the U.S. and Saudi Arabia, which has said it will retaliate against any economic sanctions or other moves against it.

"We ought to suspend military sales, we ought to suspend certain security assistance and we ought to impose sanctions on any of those that were directly involved in this murder," Schiff said.

President Trump had also talked about possible punishment but said he didn't want to halt a proposed $110 billion arms sale to Saudi Arabia because, he maintained, it would harm U.S. manufacturers.

He initially said he believed the Saudi account, and speaking this weekend the president praised the crown prince's "very good control" of the kingdom, but acknowledged "there's been lies" with the Saudis' shifting explanations.

Mr. Trump said he needs to learn more about the killing and would be working with Congress on the U.S. response. He also said he would talk soon to Prince Mohammed.

European nations demand "clarification"

Britain, Germany and France issued a joint statement condemning the killing of Khashoggi, saying there is an "urgent need for clarification of exactly what happened."

In a statement Sunday, the governments said attacks on journalists are unacceptable and "of utmost concern to our three nations." They said the "hypotheses" proposed so far in the Saudi investigation need to be backed by facts to be considered credible.

German Chancellor Angela Merkel told reporters Sunday in Berlin she supports a freeze on arms exports to Saudi Arabia. German Economy Minister Peter Altmaier underlined that point Monday, calling for a joint European position as Germany "won't at this point approve any further arms exports because we want to know what happened."