SANFORD, Fla. – A series of witnesses testified Monday morning that George Zimmerman was the voice screaming in the background during a crucial 911 recording that contained the sound of the gunshot that killed Trayvon Martin.

“Yes, definitely, it’s Georgie… I hear him screaming,” testified Sondra Osterman, one of several witnesses called by the defense on Monday. Osterman worked with Zimmerman at a mortgage firm and said she was best friends with Zimmerman’s wife.

State prosecutor Bernie de la Rionda focused on a non-emergency phone call recording in which Zimmerman said “these f****** punks, they always get away,” playing it four times during Osterman’s testimony.

Osterman identified Zimmerman’s voice in that recording but said she didn’t believe he sounded angry. Zimmerman’s anger leading up to the shooting is a key component of the second-degree murder charge against him. In Florida, second-degree murder requires “ill-will, hatred, and spite.”

Osterman’s husband, Mark, said that the voice “just sounded like George.” He noted that he spoke on the phone to Zimmerman as often as he spoke to him in person. Mark Osterman testified last week as a state witness.

Mark Osterman also taught Zimmerman how to shoot firearms. Asked if he thought he’d taught Zimmerman how to shoot properly, Osterman said “I hope so.”

Osterman also testified about the safety features of Zimmerman’s gun, a Kel-Tec 9 millimeter.

“It was chosen for the reason of, it didn’t have an exterior safety,” said Osterman, a federal air marshall. He said that no law enforcement agent he knew of carried a firearm with an exterior safety.

Geri Russo, who worked with Zimmerman at Digital Risk, a mortgage company, also testified, “I have no doubt in my mind that that’s his voice” heard screaming during the emergency call.

Leanne Benjamin is a Sanford-area real estate agent who became friends with Zimmerman. She identified Zimmerman’s voice as the scream and said “I know what his voice sounds like when he gets excited or loud.”

Monday was the second day that the subject of voice identification was considered during the trial.

On Friday, Trayvon Martin’s mother, Sybrina Fulton testified that it was her son’s voice screaming on the recording.

Later that same day, Zimmerman’s mother and uncle were the defense’s first witnesses and identified Zimmerman as the screamer.

A spokesman for Zimmerman’s defense team tells The DC that they expect their case to end by Wednesday depending upon the length of the state’s cross-examinations.