User blog comment:Gcheung28/Twilight Saga Quiz/@comment-5531582-20121106205130/@comment-3412402-20121128210508

In Eclipse (the book), it states that she did kill them but didn't drink their blood because she didn't want a part of him inside her. It doesn't state exactly when Esme slipped up, but it's implied that it was when she was a newborn.