Reread it. [spoiler]The paladin searching says it is her duty to RECOMMEND declaration of death, and makes a point to say it is not Petra's duty to officially announce it yet. At the very end of the quest line from the Reef, Petra pretty much doubles her efforts.[/spoiler] So no. I think it's too early to say for certain she's dead. I also think there's a strong possibility of her making a reappearance.