You're not wrong about that—it's not completely incriminating. But they say hindsight's 20/20 for a reason. There's probably a pretty even split possibility that it could be one thing or the other.

Even if it's true, it doesn't mean that whoever killed Charles is the same one who killed Rayfa, so it may not even matter even if that was the case the other day. [not for figuring out who the guilty party is this time at least, even though they need their comeuppance too.]