Mississippi teenage killer Carly Gregg wept in court Friday as she was found guilty of brutally shooting her mother and wounding her stepfather after they discovered her “secret life” with drugs earlier this year.

The 15-year-old sobbed as she was found guilty of all charges, including first-degree murder, attempted murder and tampering with evidence. She will spend the rest of her life in prison without the possibility of parole.

The verdict came after the jury watched chilling surveillance footage of the baby-faced teen shuffling uncomfortably around their Brandon home, a gun clutched behind her back, moments before shooting her mother Ashley Smylie, 40, a math teacher at Northwest Rankin High School, in the face.

The jury deliberated for about two hours before reaching its verdict.

Gregg, who was 14 at the time of the killing, also stood trial for shooting her stepfather, Heath Smylie, in their Brandon, Mississippi, home on March 19 after the couple learned she had a “secret life” involving drugs.

The alarming surveillance footage shows Gregg, wearing a Nirvana band shirt, disappearing off-camera into her mother’s bedroom seconds before three shots are fired. Smylie then lets out a piercing scream, the clip obtained by Law & Crime shows.

About 10 seconds later, the teenager returned to the kitchen, still with the gun strapped to her back.

Prosecutors said Gregg was watching the camera the entire time to hide the weapon, which was later identified as a .357 Magnum pistol.

Once she was back in view of the camera, Gregg could be seen grabbing her mother’s phone from the counter and calmly sitting on a stool, while her two dogs stood next to her.

Prosecutors allege Gregg then carelessly sent multiple messages, including one to her stepfather, trying to lure him to the house.

“When will you be home, honey?” the text sent to Heath reportedly read.

When Heath returned home a short time later, Gregg shot him in the shoulder before he could grab the gun from her, the court heard.

Prosecutors said the teen also texted a friend asking her to come over because there was an “emergency.”

“Have you ever seen a dead body? My mother is over there,” Gregg’s friend claimed, asking her when she arrived at the house.

Gregg committed the shooting hours after a friend tipped off her mother about the teen’s marijuana use.

When the couple returned home from school that day, the mother searched Gregg’s room and discovered a stash of vape pens, the court heard.

“The testimony of a friend shows that he was so concerned about Carly’s marijuana use, that he was so concerned about her being high and that she had these disposable phones, which (Carly’s) mother didn’t know about, that he felt compelled to tell Ms. Ashley Smylie that day,” Rankin County Assistant District Attorney Kathryn Newman said earlier in the trial.

Gregg rejected a plea deal and defended himself on the grounds of insanity. Psychiatrist Dr. Andrew Clark testified Thursday that the teen was experiencing a mental health crisis on the day of the shooting.

He said the teenager suffered from severe mood swings, hearing voices and had dissociative problems, which were made worse by her medication.

“And then her mother finds out she’s smoking marijuana,” Clark told the court. “For Carly in particular, she cared so much about her mother’s approval, so for her this was a crisis.”

Meanwhile, Gregg’s stepfather testified Tuesday that the teen — who he described as a “sweet little girl” — had no memory of the shooting.

“I’ve never seen anyone like that, not even in movies. She wasn’t herself and I don’t think she recognized me,” Heath said, adding that he and Gregg still talk daily and that their relationship is “good.”

The teen faces up to life in prison for the murder, plus 30 years to life for the other charges.