The mother of the Georgia teen accused of killing four people in a mass shooting at Apalachee High School was indicted by a grand jury last week for allegedly taping her then-73-year-old mother to a chair and leaving her alone for nearly 24 hours last year, according to a news report.

Marcee Gray, 43, is accused of exploitation and intimidation of a disabled adult or elderly person, false imprisonment, criminal damage to property in the second degree, and theft, The Atlanta-Journal Constitution reported .

Grays 14-year-old son, Colt, has been charged as an adult with four counts of felony murder for the Sept. 4 killings of two students and two math teachers at his Winder, Georgia, school.

His father, Colin Gray, 54, with whom the teens mother is estranged, has been charged with second-degree murder, involuntary manslaughter and second-degree cruelty to children after authorities said he knowingly allowed his son to possess a gun.