Updated

One of the prosecution's most important witnesses in the Trayvon Martin murder case will face a second round of defense questioning about what she heard while on the phone with the teen right before he was killed.

Nineteen-year-old Rachel Jeantel's testimony that will continue Thursday is considered important to the state's case. She was the last person to talk to the 17-year-old Martin before his encounter with defendant George Zimmerman on Feb. 26, 2012.

Zimmerman is charged with second-degree murder.

Jeantel bolsters prosecutors' contention that Zimmerman was the aggressor in his confrontation with Martin.

She says Martin told her a man was following him. Later, she heard what sounded like Martin's phone earpiece drop into the grass and she heard him say, "Get off! Get off!"