Carly Gregg, the Mississippi teen who shot her mother dead and wounded her stepfather, wept Friday as she was was found guilty of the ruthless shootings .
The 15-year-old may spend the rest of her life in prison after being convicted on all charges, which included first-degree murder, attempted murder and tampering with evidence.
The jury deliberated for two hours after watching home surveillance footage that shows Gregg, with a handgun tucked behind her back, darting into her mother Ashley Smylie’s room. Moments later, three shots could be heard, followed by a scream…