The state said Ronald Ellis committed first-degree murder. The defense didn't deny Ellis did it, but said it was not premeditated.
Taking the stand on the first day were members of Cathey's family along with crime scene investigators who walked through every detail of the scene with pictures and first-hand accounts.
One of the Target security officers on duty that night even took the stand.
"This is the guest leaving in the green," he said as Cathey can be seen walking in the parking lot.
"That's when the shot was fired."
Witnesses said Cathey ran away.
"A girl came out from between the cars holding her leg, dragging it. Bleeding, screaming. And -- (crying). Then a man came up behind her and he shot her two more times in her back," said one witness.
"That's her laying in the ground right there."
Emotions ran high as family members listened to the harrowing details.
In order for their loved one to get justice, prosecutors will now have to prove to the jury the crime was unlawful, intentional and premeditated in order to get a first-degree murder conviction.
A History of Violence
Ellis is a former Memphis firefighter with a history of domestic violence.
The victim took out a restraining order against him, trying to prevent any further violence from happening.
But that wasn't the only case against him. WREG has learned he attacked a woman while on the job.
He was fired after this latest arrest.