Why didn’t the girlfriend come forward when she learned Trayvon was dead? She had to know he was shot and killed yet, according to what I read, Trayvon’s parents only discovered the conversation between the two when they saw the cell phone records. This was weeks later. Why didn’t the girlfriend come forward immediately?
Speculation on my part, but if she heard how the fight started, she may know that Martin was 100% the aggressor, and she did not want to give that up. After being coached by a lawyer, and after the police dispatch recording came out, she was able to come up with a plausible story that didn't directly contradict the recording of Zimmerman.