A long time ago, the cloners of Kamino came to Tatooine. This was before Jango Fett, you understand.
Before anything is perfected...it isn't. Do you understand this? It's natural. It's normal. It's a necessary evil. But sometimes, true evil can arise from such trial and error. This is what happened on Tatooine.
The cloners realized they'd lost control too late. The results of their experimenting broke loose from the lab. Some say it was a couple of Jawas who broke into the lab who caused the tragedy, others that the Jawas became involved later. It makes no difference.
A man named Lars was the first victim. They were vicious, obvious mistakes. No one knows what went wrong. All of the cloners who were involved in the testing were slaughtered. After a series of barbarous raids, a name was given to the subjects for the first time. As time wore on, given the limits of civilization on Tatooine, the subjects settled down, in their own way. They earned another name.
The Lars family never forgot. One day Cliegg Lars, who had taken as a bride a slave he personally liberated, lost her in another of the raids. The woman's son was visiting Tatooine. Cliegg told him everything he knew about what had happened, and watched as the son went off with fire in his eyes. Cliegg smiled. The Sand People would finally experience what they'd done to others for countless years.
No cloners ever came back. There are some who wonder, do you blame the victims even when you have a hard time admitting who they are?