Trayvon Martin's mother to take stand in Zimmerman trial

It could be one of the most emotional and important days yet at the George Zimmerman trial today.

Trayvon Martin’s mother is expected to take the stand and discuss a critical piece of evidence: Screams heard on the 911 audio tape.

Considered the cornerstone of the prosecution's case from the beginning, the tape is said to be evidence of who was the aggressor the night Martin was shot and killed.

The prosecution is expected to wrap up its case after that powerful testimony from Sybrina Fulton.

George Howell has more on the case.

“Both parents were seen crying during testimony, Martin’s mother here with her eyes closed, and looking away as the jurors were shown graphic pictures of her son's lifeless body,” Howell reports.

“The main focus of Fulton's testimony will no doubt be her account of whose faint cries for help she believes are on that tape.”