They asked if someone saw Abby or another female in these clothes.
Who else would have worn them besides Abby?!?!?!
I think the intention was-- 'even if you didn't specifically recognize the female as Abby, please contact us if you saw someone wearing these clothes'. That was my take, at least. Additionally, I guess it is possible Abby returned with her hair shorter or dyed another color. A passerby may think-- 'Hm, I saw a girl wearing something like that but she was blonde so couldn't have been Abby'.