He cited software that is widely used in Europe and has become recently accepted in the United States that examines characteristics like pitch and the space between spoken words to analyze voices. Using it, he found a 48% likelihood the voice is Zimmerman's. At least 60% is necessary to feel confident two samples are from the same source, he told CNN on Monday -- meaning it's unlikely it was Zimmerman who can be heard yelling.
The experts, both of whom said they have testified in cases involving audio analysis, stressed they cannot say who was screaming.