An 18-year-old from the Riverland region is expected to appear in the Adelaide Magistrates Court this afternoon charged with solicit to murder, according to SA Police.
The accused, who was already charged with four aggravated counts of threatening to kill, was arrested by police from Task Force Murray this morning.
The task force, led by the SA Police Major Crime Investigation Branch, has been responsible for investigating an attack allegedly being planned at a school in the Riverland region.
The 18-year-old is the second person charged with solicit to murder in connection with the incident, with the first, a 16-year-old, next due to appear in Adelaide Youth Court 5 December having been remanded in custody.
The offence of solicit to murder carries a maximum penalty of life imprisonment.