Trayvon Martin's father has testified that he never denied it was his son's voice in screams for help on a 911 call.
Tracy Martin said Monday that he merely said he couldn't tell if it was Trayvon Martin after his first time listening to the call.
Tracy Martin's testimony came after the lead investigator testified that Tracy Martin had answered "no" when he asked if the screams belonged to Trayvon Martin.
Special section: George Zimmerman trial
Convincing the jury of whose voice is on the tape is important to both sides because it would help jurors decide who was the aggressor in the confrontation that left Martin dead. Relatives of Martin's and George Zimmerman's have offered conflicting opinions about who is heard screaming.
Zimmerman is pleading not guilty to second-degree murder, claiming self-defense.