She does, right after 4:05 minutes in the final recording at this link:
http://www.huffingtonpost.com/2012/03/16/trayvon-martin-911-audio-_n_1354909.html
Starting at 3:30
Caller: I didn't see 'cause it was too dark, and I just heard people screaming Help me help me and this person shot him. He was like wrestling with him, on the ground from what I could see, it's very dark. I think it's a police officer that's there... the man didn't try to run away or anything.
911 Operator: And can I get your name please?
C: (Gives name) but I don't wanna be a witness or anything...
911: That's ok, I'll leave you as anonymous.
C: I'm just scared. I mean I can't, I can't even believe, and I--it's--this is, the person, oh my god, I don't--it's a young boy or something I just I can't imagine, I've never seen anyone killed...