But West said that doesn't prove anything, arguing that crime-scene technicians didn't properly protect Martin's hands from contamination.
Two police dispatch phone calls that could prove to be important evidence for both sides were played for the jury by the defense. Martin's mother, Sybrina Fulton, left the courtroom before the second recording, which has the sound of the gunshot that killed Martin.
The first was a call Zimmerman made to a nonemergency police dispatcher, who told him he didn't need to be following Martin.
The second 911 call, from a witness, captures screams in the distant background from the struggle between Zimmerman and Martin. Martin's parents said the screams are from their son, while Zimmerman's father contends they are his son's.
Nelson ruled last weekend that audio experts for the prosecution won't be able to testify that the screams belong to Martin, saying the methods used were unreliable.
Other witnesses who testified Monday included a convenience store clerk and the 911 dispatcher who took Zimmerman's call when he was following Martin, who had gone to the convenience store to buy Skittles and a can of iced tea.
The 911 dispatcher, Sean Noffke, testified that he had advised Zimmerman not to follow Martin.
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