A New Generation Edit
When the Jawas sold C-3PO and Red to Owen Lars, only to have Red short-circuit as they were leaving, Owen asked the Head Jawa what he was trying to pull. The Head Jawa protested that Red had passed a full diagnostic that morning. When 3PO talked Owen into buying R2-D2 instead of Red, the Head Jawa asked Owen if he'd want the extended warranty on R2.
The next day, Adam, R2, and 3PO met Obi-Wan, who revealed to Adam that his real name was Luke Amidala. Later that day, Luke (as he'll be called from now on), Obi-Wan, R2, and 3PO came across the Jawas who had sold R2 and 3PO to the Lars family, only to find that all of them (including, presumably, the Head Jawa) had been slaughtered. Obi-Wan determined that the laser blasts that killed them were far too precise for Sand People, and it couldn't have been clone troopers because they were rubbish at shooting. Obi-Wan decided it must have been Owen and Beru, that they must have gone on a murderous rampage looking for Luke.