Sellars was initially charged with one count of assault on individuals with a disability.
Cooper eventually died from her wounds, and the North Carolina Office of the Chief Medical Examiner ruled her death a homicide due to assault.
Investigators reviewed the Medical Examiner's report and consulted with the District Attorney's Office. On Tuesday, Oct. 24, police said they obtained a felony warrant for Sellars on one count of murder. Officers booked her into the Johnston County Detention Center, and she remains held without bond.
Sellars was scheduled to appear in court Wednesday, Oct. 25.