Hard to say since we don't know how they were killed. More importantly tho, we don't know if they had turned before they were killed......
Well, Hurd did refer to it as murder...and if Carol or whomever just put down two walkers, I don’t know why they would cover it up, you know? But ever since Sunday night, I’ve been having trouble understanding why Carol would kill two people who had already been placed in isolation. She would have to know that others had already been infected, and that murdering Karen & David wouldn’t serve as any kind of protection for the group.
See how this show messes with your mind? I can’t even accept a simple plot point without trying to over-analyze, LOL.