In the last 45 seconds of the 911 call, there is a faint voice, a distant yell, and the urgent dialogue between a woman and the operator.
"There's just someone screaming outside," the caller begins on the recorded line.
There is more distant yelling obscured by the operator -- "Male or female?" -- and the caller -- "I think they're yelling help, but I don't know."
There is a high-pitched scream, a kind of cry, and then the clearest sound of all.
"There's gunshots. Just one," the woman says on the only 911 call that recorded what was happening in the dark at the Retreat at Twin Lakes, a gated townhouse community in Sanford, Fla., on the night of Feb. 26.
Those recorded 45 seconds turned out to be a recording of the end of Trayvon Martin's life.
And amid the conflicting, hazy and at times emotional reports from neighbors who heard and glimpsed only fragments of what was happening during those crucial seconds, the audio recording of them -- from the start of the call at 7:16:11 p.m. until the gunshot at 7:16:56 p.m. -- is perhaps the closest that prosecutors and defense attorneys may come to an objective witness to the events that night.
It remains unclear exactly how the recording might be used in the court case, in which neighborhood watch volunteer George Zimmerman, 28, who said he shot the unarmed 17-year-old in self-defense, is charged with second-degree murder.
Zimmerman defense attorney Mark O'Mara said Friday on CBS that the recording would require "a lot of forensic work-up."
Last week, Florida special prosecutor Angela Corey released a trove of documents including an FBI analysis stating that the recording is inconclusive and a witness list that has two audio experts who have said the opposite.
Legal experts say the recording could be enormously important or disastrous for either side, depending on what a jury determines it can hear.
But what happens when a potentially crucial piece of evidence is a poor-quality recording of overlapping voices and unintelligible yells, essentially a wilderness of sound?
The answer may come down to which expert you ask.
One of those experts is Alan Reich, and his answer is that he is certain he can hear a young man he concludes is Trayvon pleading for his life, from the start of the recording until the end.
"I'm begging you," he hears the younger of the two men yell.
Twenty-six seconds later: "Help me."
In the last second before the gunshot, a high-pitched "Stop!" is heard.
In an effort to find out what might be discerned from the crucial 911 call, the Post retained Reich, 67, a former University of Washington professor with a doctorate in speech science.
Where many people have heard only vague yells, Reich said he has found language. He also identified two male voices outside, in the background of the recording that he concludes are those of Trayvon and Zimmerman.
At 7:09:34 p.m., Zimmerman was driving out on an errand, armed with a 9mm Kel-Tec semi-automatic pistol, when he called Sanford police to report "a real suspicious guy." That person was Trayvon, who was walking back to the townhouse where he was staying with his father.
Cursing under his breath, Zimmerman got out of his truck and began to follow him. The dispatcher told him to stop, and at 7:13:38 p.m. the call ended.
From that point until the gunshot at 7:16:56, there are different versions of what happened.
Prosecutors have said that Zimmerman ignored the dispatcher and confronted Trayvon and that a struggle ensued. A friend of Trayvon's who was on the phone with him at the time said he told her that a man who looked "crazy and creepy" was following him, according to the friend's interview with a prosecutor, released Thursday.
Zimmerman's family has said that he was walking back to his truck when Trayvon attacked him, punching his nose, knocking him down and beating his head into the sidewalk until he managed to fire his gun.
However it happened, what is certain is that soon after Zimmerman hung up with the dispatcher, he and Trayvon came face to face, and neighbors began to hear yelling.
And at 7:16:11, a woman's 911 call began recording the sounds.