User blog comment:Zathronas/Speculative author: Who is Summer Rose?/@comment-9464517-20140809092857

The thing is, tying it in with the White Fang and the Schnee family may seem convenient and all, but it would mean Ruby would harbour a lot of distrust for both groups, and would probably have mentioned so by now.

I think Ozpin's notorious "silver eyes" comment bears a lot of significance here. I would suggest that Ozpin was indeed Summer's teacher, as many have likewise suggested.

Alternatively, Ruby may not have discovered how her mother died, and it may serve as some kind of big shocking reveal later on in the show. That allows people to speculate on whether it was the White Fang or whoever.