^ I remember it as well. And it came in discussions Picard was having with Guinan, whose word Picard holds in high standing. Furthermore, Sela confirmed the existence of survivors while talking about her past and her mother.
If you'll pardon the double negative, I can't NOT see Picard delving further into this matter. Given how he laid into Wesley Crusher later on in that season about the first duty of a Starfleet officer being truth in its myriad forms, it would be hypocritical of him to let this go.