Much of the commentary in the Trayvon Martin case has centred on the lack of evidence to contradict the claims of the shooter Robert Zimmerman's claim of self-defence. See here for a summary of the case.
However, there are available a series of 911 calls, which provide a backdrop to the circumstances of the death:
The first is the crucial call from Zimmerman, the armed self-appointed Neighborwood Watch captain, in which he reports to the Police his suspicions about the black male he thinks is up to no good or is on drugs, who runs away and who Zimmerman follows, contrary to instructions given to him in the call.
The second is a call from a witness, who reports hearing cries for help and gun-shots, both of which appear to be recorded on the call.
A third records another witness hearing the calls of help and gun-shots, as well as making observations of a person apparently dead on the ground, hearing Zimmerman admit he shot the person, and seeing Police arrive on the scene. She later speaks about having earlier seen the two wrestling.