George Zimmerman's trial in the murder of Trayvon Martin resumed Thursday with a cross-examination of the victim's childhood friend Rachel Jeantel from Miami by the defense team.

The 19-year-old took the witness stand for the second day and described her phone calls with Trayvon in the moments before he was shot dead on Feb. 26, 2012.

Jeantel spoke in a soft voice, which prompted defense attorney Don West to ask her to speak up as she recalled her statements made to the media after Martin's death.

Jeantel, one of the most important witnesses for prosecutors in the case, was a childhood friend of Martin's since elementary school. On Wednesday, she testified that Trayvon "kept complaining that a man was just watching him." She claimed that Trayvon asked Zimmerman, "why are you following me" and heard him say "get off". However, during her cross-examination by the defense today, she said she did not initially mention hearing those words in her initial statement because she didn't think they were important at the time.

Zimmerman is charged with second-degree murder in the death of Trayvon Martin, who was shot to death when a fight broke out between himself and Zimmerman on his way back from a local convenience store last year.

The prosecutors claim that Zimmerman, who was a neighborhood watch volunteer, followed and shot Trayvon, while the defense claim that Trayvon aggravated Zimmerman who then shot him in self-defense.

An all-female jury will decide whether Zimmerman is guilty. If he is found guilty, he will face up to life in prison.

Over the first three days of the trial, the prosecution has been pushing its case aggressively as they try to convict Zimmerman. As the prosecution brought out its witnesses, the defending attorneys have attempted to undermine the credibility of them, and create doubt in their reliability among jurors.

Jeantel was already questioned for 90 minutes on Wednesday, highlighting two lies she told – her age, and why she did not attend Martin's funeral – in an attempt to show she cannot be trusted as a witness.

The witness had tried to convince people that she was just 16 years old, hoping that she would be considered a minor and be afforded more privacy.

In addition, she lied about why she did not attend Martin's funeral, saying that she was in the hospital at the time.

However, it was revealed that she had lied on both accounts. Under questioning from the defense team she admitted: "You got to understand. You're the last person to talk to a person and he dies on the phone after you talk to him. You got to understand … you don't know how it felt. Did I really want to go see the body after I'd just talked to him?"