There's a fan theory that it was possibly Boba Fett who killed Uncle Owen and Aunt Beru in A New Hope, instead of Storm Troopers, as Obi-Wan thought).
This is a big jump (that Obi Wan was wrong) — but listen to the reasons in favour of this idea:
Boba Fett was reasonably close by at Mos Eisley with Jabba (according to Canon)
Vader was clearly frustrated at how slow his men were going, and in The Empire Strikes Back we see the Empire resort to using Bounty Hunters to solve a problem.
Storm Troopers have no reason to cover up the murdering of Jawas by making it look like Sand People attacked. Whereas a Bounty hunter would want to prevent other Bounty hunters from grabbing his prize.
In The Empire Strikes Back, Vader reprimands Boba Fett saying
I want them alive - no disintegrations!
This seems to be a hint that Boba Fett got it wrong last time.
Who else have we seen disintegrated? The Jawas, Owen and Beru.
Disintegration wouldn't happen by blaster fire or even a Lightsaber. It would take more, it would take burning the bodies.
We know Fett has a weapon on his arm to easily burn a victim of his choosing.
My question is: Is there any evidence to suggest that Aunt Beru and Uncle Owen were killed by Boba Fett and not the Storm Troopers?