Defense testimony has begun in the first-degree murder trial of a former Publix employee accused of shooting a co-worker.

Arunya Rouch is accused of killing Gregory Janowski after she was fired from the Tarpon Springs store in March 2010. Her lawyers have asserted she snapped after she was teased, called racial names and fired.

The defense team's psychiatrist, Dr. Carl Jones, told the jury this afternoon Rouch could not distinguish between right and wrong when she returned to the store because Janowski was constantly bullying her.

"Greg was an ongoing stressor," Jones said. "It was happening every day for two years. Every day, she had to get up and go to work with the fear that this person would be there, that this person would be bullying her, this person would be criticizing her."

Jones said Rouch told him she tried to commit suicide and always had problems at work. She said she told her husband she was "sick in the head" six weeks before the shooting, Jones said.

As the problems progressed, Jones said, Rouch "started to think about dying and also killing someone as well. She said she couldn't stop the thoughts; they were repeating themselves to her in the sense she could not control them."

Jones said Rouch has disassociation disorder and had a major depressive episode with psychotic features. He said that because of the bullying by Janowski, Rouch exhibited symptoms similar to those of post traumatic stress disorder.

The state is planning on calling three doctors of its own who believe Rouch was not insane at the time of the murder.

Earlier Tuesday, before resting their case, prosecutors played surveillance video showing Rouch walking inside the Publix allegedly looking for more targets.

She takes the elevator and makes her way down the aisle.

She is seen with a green Publix bag. A co-worker puts her arm around her and tells her to calm down.

Next, though, Rouch's boss is seen running form the meat counter after Rouch allegedly fired on him. 

Cameras around the store caught the dramatic event. There was also a 360-degree roving camera that recorded customers and employees frantically trying to escape the store once they heard gunshots.

Rouch also is charged with attempted murder of law enforcement officers for allegedly firing her gun at two officers inside the store. She faces life in prison.