Here is a timeline of events before and after he disappeared:
May 2018: Khashoggi meets Hatice Cengiz, a 36-year-old Turkish Ph.D. student, at a conference in Istanbul and she soon becomes his fiancée.
Sept. 28: Khashoggi visits the Saudi Consulate in Istanbul for the first time to pick up a permission document to marry Cengiz. He's told to come back later.
Oct. 1: He returns to Istanbul after a trip to London.
Oct. 2: Khashoggi goes back to the Saudi Consulate in Istanbul. Cengiz waits for him outside for 4 hours, but he never comes out, and she is told by consulate staff that he left out a back door. Cengiz contacts the Turkish police.
Oct. 7: Saudi government officials deny involvement in Khashoggi's disappearance after Turkish officials report that he was killed.
Oct. 8: Sen. Lindsey Graham, R-S.C., warns the Saudis of consequences if the government is found to be complicit in Khashoggi's disappearance.
Oct. 9: Cengiz writes an op-ed in The Washington Post, saying Khashoggi had applied for U.S. citizenship and that his reason for visiting Turkey was to take care of all necessary paperwork for them to marry before he returned to Washington D.C. She urges President Donald Trump and first lady Melania Trump to "help shed light on Jamal's disappearance." State Department spokeswoman Heather Nauert, who has since been nominated by Trump to become U.S. ambassador to the United Nations, said of Khashoggi's disappearance, "We're not going to make any judgments about what happened to him. We don't know what has happened to him. We don't have any information on that.
Oct. 10: Trump makes his first comments on Khashoggi's disappearance, saying he contacted the Saudis and invited Cengiz to the White House. "We're demanding everything," he said. "We want to see what's going on here. That's a bad situation. And frankly the fact that it's a reporter you could say in many respects it ... brings it to a level. It's a very serious situation for us and this White House. We do not like seeing what's going on."
Oct. 11: The Washington Post, which Khashoggi wrote for, reports the Turkish government told U.S. officials that it had audio and video recordings proving Khashoggi was killed inside the Saudi Consulate in Istanbul.
Oct. 13: Cengiz writes another op-ed, this one in the New York Times, on what would have been Khashoggi's 60th birthday, this time referring to him in the past tense. "Jamal and I had many dreams, but the most important one was to build a home together," she wrote.
Oct. 14: In an interview that aired on CBS's "60 Minutes," Trump addresses Khashoggi's disappearance. "There's something really terrible and disgusting about that if that were the case," he said, referring to allegations by Turkish authorities that Saudi Arabia was involved. "So, we're going to have to see. We're going to get to the bottom of it, and there will be severe punishment." In an apparent response to Trump's comments, a Saudi official said if any moves were taken against the kingdom "it will respond with greater action."
Oct. 15: Trump says he spoke with Saudi King Salman bin Abdulaziz Al Saud for 20 minutes and that the king "denies any knowledge" of what happened to Khashoggi. Trump suggests Khashoggi was targeted by "rogue killers" and says he is sending Secretary of State Mike Pompeo to Saudi Arabia to speak to the king. Meanwhile, Turkish police are allowed to search the Saudi Consulate in Istanbul for the first time.
Oct. 19: A Saudi official tells ABC News that Khashoggi was killed when he was "placed in a chokehold position" to prevent him from calling for help and leaving the country's consulate in Turkey.
Oct. 23: In a speech to Turkey's Parliament, Turkish President Recep Tayyip Erdogan says the killing of Khashoggi was planned by the Saudis. "The information and evidence we have gathered until now shows that Khashoggi was the victim of a murder which was savagely planned,” Erdogan says.
Oct. 24-25: Reports surface that President Trump was briefed by CIA Director Gina Haspel on the latest in the U.S. investigation into how Khashoggi was killed in the Saudi Consulate. The Washington Post reports that Haspel had listened to audio purportedly capturing Khashoggi's killing.
Oct. 31: Turkish prosecutor Irfan Fidan publicly confirms for the first time that Khashoggi was strangled as soon as he stepped into the Saudi Consulate in Istanbul and his body was dismembered.
Nov. 16: Family and friends of Khashoggi gather for his funeral at Istanbul's Fatih Mosque, one of the city's oldest and most magnificent.
Nov. 17: President Trump says that it's "too early" to say whether Saudi Prince Mohammed bin Salman was behind the killing of Khashoggi, and describes multiple news reports saying the CIA has concluded the crown prince was directly involved as "premature."
Nov. 20: A U.S. State Department official who had seen a version of the CIA's assessment on the murder of Khashoggi tells ABC News it's "blindingly obvious" that Prince Mohammed bin Salman ordered Khashoggi's murder.
Nov. 28: Pompeo and Defense Secretary James Mattis issue their most definitive dismissals yet of the CIA's reported assessment that Saudi Crown Prince Mohammed bin Salman ordered Khashoggi's killing. "There is no direct reporting connecting the crown prince to the order to murder Jamal Khashoggi," Pompeo tells reporters shortly after briefing all senators behind closed doors on Saudi Arabia and Yemen, declining to say more in an unclassified setting. Mattis later tells reporters, "We have no smoking gun that the crown prince was involved. Not the intelligence community or anyone else."
Dec. 4: CIA Director Haspel briefs a limited group of senior senators on the role top Saudi Arabian officials played in Khashoggi's death. Following a briefing, leading Republican senators, including Senate Foreign Relations Chairman Bob Corker, R-Tenn., tells reporters that there was "zero question" that Saudi Crown Prince Mohammed bin Salman ordered the brutal murder. Republican Sen. Lindsey Graham, R-S.C., said, "There's not a smoking gun, there's a smoking saw."
Dec. 6: Congressional supporters of bipartisan legislation designed to strongly rebuke Saudi Arabia for the role its crown prince allegedly played in the death of Khashoggi, say they believe they have secured enough votes for final passage. Mattis tells reporters, "We are continuing to review. I am quite satisfied we will find more evidence of what happened. I just don't know yet what it's going to be or who's going to be implicated, but we will follow it as far as we can."
Dec. 11: Khashoggi named Time magazine Person of the Year along with persecuted journalists and the Capital Gazette newspaper of Maryland which was targeted in a mass shooting. "This is the first time we've ever chosen someone no longer alive as the Person of the Year," Edward Felsenthal, Time editor-in-chief. "But it's also very rare that a person's influence grows so immensely in death."
"His murder prompted a global reassessment of the Saudi Crown Prince and a really long overdue look at the devastating war in Yemen."