Carly Gregg, the 15-year-old murder suspect, was captured on home surveillance cameras in chilling footage that allegedly shows her shooting her mother and attempting to kill her stepfather.
The video, captured on the family's kitchen surveillance camera, was shown in court Wednesday and allegedly shows Gregg taking a .357 Magnum handgun to her mother's room and shooting her.
Gregg was also charged with aggravated assault for wounding her stepfather, Heath Smylie, and tampering with evidence for hiding a security camera after the shooting.
Mississippi Teen Murder Suspect's Chilling Video Evidence
Gregg's defense attorney did not deny that she had killed her mother but attempted to prove that the teen was suffering from a mental health crisis and did not remember the shooting.
However, prosecutor Michael Smith argued that Gregg "knew what she did and knew the difference between right and wrong."
Mississippi Teen Murder Suspect's Chilling Video Evidence
The jury found Gregg guilty on all counts, and prosecutor Kathryn Newman said Gregg had shown "zero remorse."
Gregg was sentenced to life in prison on the first and second counts, and 10 years on the third count.
Mississippi Teen Murder Suspect's Chilling Video Evidence
The ruling came after a week-long deliberation into the shocking murder of Smylie inside the family's home.
In the video, Gregg is seen texting her stepfather in an attempt to lure him home and ambush him.
Mississippi Teen Murder Suspect's Chilling Video Evidence
When Heath Smylie took the stand Tuesday, he testified that when he opened the kitchen door, "the gun went off in my face before the door was even three to four inches wide open, and everything kind of went pretty fast from there."
"The gun flashed in my face," he said. "It went off two more times, but my hand was on the gun after the first shot, and I twisted it from Carly."
Heath was shot in the shoulder during the encounter with Gregg, police said.
During the trial, expert witnesses provided insight into Gregg's mental state. Dr. Andrew Clark, a child and adolescent psychiatrist, testified that he did not believe Gregg was able to understand the nature of her conduct and appreciate the difference between right and wrong at the time of the incident.
However, prosecutor Michael Smith argued that Gregg "knew exactly what she was doing and knew the difference between right and wrong."
In closing arguments Friday, Smith said, "Ladies and gentlemen, there's no doubt Carly Madison Gregg is the one who killed her mom, Ashley Smylie. There's no doubt that she attempted to kill Heath Smylie, when she aimed the gun right at his head and shot and hit him. And there's no doubt that she's the one who hid the camera, thus tampering with evidence."
"She knew exactly what she was doing, and she knew the difference between right and wrong," Smith said.
