Technically, the difference between archeology and grave robbing is a college degree
Ash wasn't impressed though. "So you're grave robbing?" Ho'olheyak glared at him. "It's archeology! Those graves are thousands of years old! We can dissect them for their secrets!" Ho'olheyak had a mad grin on her face.
"Who are you yelling at?" Ruby smiled coldly as she pulled out Yang's right eye, causing her to scream in pain. "Unlike before, I'm in no hurry to sacrifice you." Ruby's eyes softened as she carefully placed the plucked eyeball to the side and gently wiped the blood from Yang's cheek. "So relax while I take my time torturing you. Do not think I haven't found out about your plan for me once Taiyang is done with me."
Crazy voices, are you guys ready for the answer? Eh, most of you might not be. The answer is that Taiyang killed Summer when she tried to escape with Yang and Ruby. They were both infants at the time. As for what was the reason for Summer escaping? She also learned about Taiyang's semblance, however, unlike Raven. Summer helped raise her before Taiyang chose Summer as his new wife and gave birth to Ruby.