The king and prince met with Khashoggi's brother and son in Riyadh, where the royal Saudi leaders offered "deepest condolences" and sympathy to the reporter's family.
"May God rest his soul," the Saudi Foreign Ministry tweeted Tuesday.
The meeting came four days after the Saudi government first acknowledged that Khashoggi had died after visiting a Saudi consulate in Turkey Oct. 2. Details of what happened to the writer have been slow to emerge.
Earlier Tuesday, Turkish President Recep Tayyip Erdogan said Khashoggi's was a "brutal" and "political murder" that requires an independent investigation and trial.
Erdogan revealed new details in the disappearance of the Washington Post columnist, including that a consulate team scouted out the Belgrad Forest on Oct. 1, the day before Khashoggi died.
His speech before parliament Tuesday stopped short of any claims linking the attack to bin Salman, who wasn't mentioned.
Erdogan said a team of 15 Saudis flew to Istanbul early in the morning on Oct. 2, including a forensic expert and intelligence officers. They removed the hard discs from the security cameras inside the consulate.
When Khashoggi arrived at the consulate, his fiancee Hatice Cengiz stayed outside and started to become concerned when he didn't return. Khashoggi told Cengiz to raise an alarm if he didn't come out after four hours. Cengiz called an adviser to Erdogan.
One of the Saudis donned Khashoggi's clothes, glasses and a fake beard to give the illusion that he'd left the building. Security cameras tracked him through town to a crowded area, where he changed clothes in a bathroom and ditched a bag in a trash can.
Saudi officials initially denied Khashoggi's death, but Friday acknowledged he'd been killed. Authorities arrested 18 Saudis, including the 15-member team identified by Turkish investigators.
Erdogan also said Tuesday there's a social media campaign to denigrate Turkey's credibility and they know who was behind it.
Erodgan asked where Khashoggi's body was hidden, who ordered the hit team to Istanbul and why it took nearly two weeks to open the consulate building to investigators. He also said the Saudis had a "local cooperator" who took the writer's body and called on them to reveal who that person is. He also noted Khashoggi first visited the Saudi consulate on Sept. 28.
Erdogan did not mention audio recordings leaked to a Turkish state-run newspaper that indicate Khashoggi had his fingers cut off during an interrogation and was beheaded and dismembered.
He also did not identify any members of the 15-man hit team, though Turkish intelligence has shown scanned passports that identify them, including some who are believed to be in bin Salman's inner circle. U.S. officials have said such a death could not have happened without the crown prince knowing about it.