The king and the clown prince of Saudi Arabia ordered a son of Jamal Khashoggi to appear in front of them so they could express their condolences for the murder of his father. This is an attempt by the King Salman to show that his son Mohammad bin Salman is innocent of ordering the premeditated murder of Khashoggi. The audience for the pictures (and video) is the Saudi public which seem unconvinced. But the act is also an insult as Khashoggi's body has not been found* and remains unburied.
The gaze is telling.

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Sahal Khashoggi is the oldest of the four children of Jamal. Three of them live in the United States. Sahal is banned from leaving Saudi Arabia.

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Notice that his robe is not pressed as the usual etiquette would require. He must have been called up on short notice or was dragged before the king. Also notice that the hand of the bodyguard in the background is right on his pistol.
There seem to be a lot of conspiracy theories being weaved around the case. Some of them were mentioned in the comments here. I don't buy it. Turkey did not arrange the incident. I see no sign that the U.S., Israel, Qatar or the UAE had a hand in this. This was a very stupid crime committed by Mohammad bin Salman. Or even worse, a mistake. The wannabe-sultan Erdogan is a crafty politician. He is simply riding the wave.
Alastair Crooke explains why the Khashoggi murder, while not unusual, has this large effect:
When a single additional, undifferentiated, snowflake can touch off a huge slide whose mass is entirely disproportionate to the single grain that triggers it. Was Khashoggi’s killing just such a trigger? Quite possibly yes – because there are several unstable accumulations of political mass in the region where even a small event might set off a significant slide. These dynamics constitute a complex nexus of shifting dynamics.
Crooke sees three traditional strategic positions that already reached tipping points and are likely to change due to this event: the U.S. relations with Saudi Arabia, Turkey's role in the Middle East and Israel's strategic defenses.
On the U.S.-Saudi relations side it is likely Congress, not the White House that will push the issue. There will be another Senate vote next month to end U.S. complicity in the war on Yemen. It is now likely to pass.
The usefulness of Saudi Arabia for the U.S. has been in doubt for some time. A Wall Street Journal op-ed by Karen Elliott House tells the White House to act:
As the Trump administration wrestles with whether to buy Saudi Arabia’s belated and befuddled explanation for the death of Jamal Khashoggi, a thoughtful Saudi tells me: “Morality aside, the critical question is the sanity of our very own Caligula.”
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If the crown prince loses power it could be either by the gentle hand of his father or, like Caligula, at the violent hand of cooperation between disgruntled princes and praetorians.
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What this would mean for U.S.-Saudi relations is anyone’s guess. Surely, however, if Mr. Trump has the ability to influence events, the first scenario is far preferable to the second.
Saudi Arabia under an unstable ruler is a burden. Not only for the U.S. but also for the rest of the world. It's time to remove him.
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*The earlier 'news' today that the body has been found came from one unreliable 'source' and was officially denied.