Just a thought.
Also, I think the fact that Rowena did some backpedaling about the O'Connors might be significant...case in point,
When Rowena first meets Mac (in Darkfever - pg 27 I think in the paperback) she identifies Mac as an O'Connor and says she'll be having a word with Mac's kin (O'Connors, right?) about Mac staring down the first Fae she sees. But she then says there are no O'Connors left, except Mac. That seems highly suspicious.
I just don't trust Rowena any farther than I could throw her though, so I might be biased. And I definitely couldn't throw her very far.
I kind of have wondered throughout the novels if Rowena didn't kill Mac and Alina's biological mom, and maybe even Alina! She could hang with the Shades she's so shady.