NEVADA, Iowa -- The second week of the murder trial of Alexander Kozak is underway in Story County.
The jury heard co-workers' testimonies about their views of the 23-year-old who gunned down 20-year-old Andrea Farrington at the Coral Ridge Mall last June.
Saiprasong Insisiengmay, director of security at Coral Ridge Mall, said Kozak was friendly but reserved.
"I told him, 'You're a good guy. Just do a better job,'" Insisiengmay testified.
Kozak reportedly had been written up for something job-related that happened the week before. He had just found out the day of the shooting.
A friend and co-worker described Kozak as being "shaking mad" just hours before the shots were fired.
“His face was flushed, red, like he was angry and his hands were continually shaking, and you could even see it in his jaw, in his cheeks because he was just so angry. It looked like he couldn't control himself,” said Deana Brown.
Kozak's defense is trying to show that he snapped when he gunned down Farrington so he isn't guilty as charged. While Kozak was visibly upset before the shooting, his anger didn't have to do with Farrington, but rather a work-related issue.
And this wasn't he first time Kozak was disciplined at work. He was told to stay away from Farrington after she complained that he was "creeping her out."
“She had received a note on her car from Alex in regards to going to a concert, and she told me she felt creeped out about it. It was left on the windshield of her car,” said Wendy Robbins, Kozak's supervisor at Coral Ridge Mall.
Robbins said Farrington had complained that she had a problem with Kozak.
“I just told him that he needed to stay away from the Guest Welcome Center because she had, Andrea, had felt uncomfortable,” Robbins said.
No one knew Kozak, who is married, and Farrington were in a secret relationship of sorts.
“I would have asked him to stop because of the potential, being married. I just wouldn't have liked that,” Insisiengmay said.
Among the 8,000 text messages sent between Farrington and Kozak, some said "I love you."
Overall, Kozak's coworkers and supervisors say he had no problem doing his job. They weren't concerned about any anger issues, violence or with his mental health. They said the shooting came as a surprise.
The state maintains he murdered Farrington after she called off their relationship.
Check back for trial updates.