Video Shows Carly Gregg Allegedly Carrying Out Murder of Her Mom

A 15-year-old Mississippi girl has been charged with murdering her mom -- and the events leading up to the fatal shooting were caught on camera -- as well as the victim's chilling screams mixed with gunfire.

Check out the footage ... which begins with Carly Gregg in a Nirvana shirt lurking around her house. At one point, Gregg peeked her head into the kitchen while holding something behind her back, later revealed to be a .357 Magnum handgun.

She then strolled out of frame into another part of the residence before several gunshots could be heard along with her mom, Ashley Smylie , yelling in pain.

Gregg calmly walked back into the kitchen area with Smylie's cell phone, texting her stepfather, Heath , to lure him to the home.

When Heath arrived there, Gregg allegedly shot him in the shoulder as the two grappled over the gun. Heath managed to wrest the firearm away from Gregg, who fled the scene, but was soon arrested and charged with Smylie's murder and other serious crimes.

The shocking video from the March 19 shootings was played Tuesday in a Rankin County courtroom during Gregg's murder trial, which has received national attention. Prosecutors initially offered Gregg a plea deal, but she turned it down and her attorneys are now pursuing an insanity defense.