PEACHTREE CORNERS, Ga. » Police in metro Atlanta say they have arrested a woman who held her newborn grandchild hostage following a domestic argument.

Gwinnett County police Cpl. Michele Pihera said in a statement a four-hour standoff with a SWAT team ended peacefully today. She says the 4-week-old baby was unharmed and the child’s grandmother, 57-year-old Laurie Morgan, was charged with aggravated assault and reckless conduct. It was not immediately known if she had an attorney.

Police say the standoff began with a domestic argument at an apartment where Morgan grabbed the baby while holding a gun, then walked outside with the child and fired a gunshot.

Police dispatched a SWAT team, which entered the apartment and arrested Morgan.