It was stated up-thread that Martin was walking towards his destination, still on the phone with his girlfriend, when Zimmerman caught up to him. Martin's last words, which she heard, were addressed to Zimmerman: "Why are you chasing me?"
No, not chasing.
“Trayvon said, ‘What, are you following me for?’ and the man said, ‘What are you doing here?’ Next thing I hear is somebody pushing, and somebody pushed Trayvon because the head set just fell. I called him again and he didn’t answer the phone.”
Then the line went dead, she said.