Prince Choppy Choppy can't even get rid of 1 guy without the whole world noticing. But to clutch my tinfoil hat, if Saudi Arabia really did want to do this, Prince Choppy Choppy could've told Biden "We're doing this, I know you can see us, but be quiet and you'll get your cheap oil, OK?".
Although if Biden took part in such a conspiracy, someone in one of the American intelligence agencies would've probably leaked it out.