SANFORD, Fla. -

Day 13 in the George Zimmerman trial Wednesday began with a dramatic 911 call from a woman who was haunted by a cry for help.

She said she saw two people. After the shots, she saw a man get up, and a body on the ground.  The body, now Jayne Surdyka knows, was that of Trayvon Martin. The man who got up from the ground was George Zimmerman.

On Feb. 26, 2013, Surdyka said she took a shower, was reading and had the T.V. muted, as she waited for a show to come up.  Then she heard noise outside and opened her window.

"I heard a very aggressive voice. Some one sounded very angry, very agitated," Surdyka said.

The triathlete lives alone with her cat. It was raining and it was dark outside.

Two people "were on the ground and they were wrestling," she said.

Suddenly she said she heard, "POP, POP, POP."

Prosecutor Bernie de la Rionda played the 911 call she made. There were tears in the courtroom.

Surdyka said she was convinced Trayvon was the one crying for help. Defense attorney Don West told her that was an assumption.

Witness testimony continued Wednesday afternoon. If Zimmerman is found guilty of second-degree murder, he could serve life in prison.