Yazoo County District Attorney James Powell said since this week's incident involved the use of a firearm and an individual age 13 or above, the unidentified teen could face adult charges in circuit court, The (Jackson, Miss.) Clarion-Ledger said Thursday.
School officials said the girl involved in Tuesday's incident claimed to have been the victim of bullying, adding the teen never informed her teachers the allegation, the report said.
The young girl stands accused of pulling out a .380-caliber semi-automatic pistol on board a crowded school bus before issuing a series of threats.
Authorities said the incident came to an end after one of the girl's peers, Kaleb Eulls, tackled and disarmed her.
"Even though he was raised right, what put him in the thought to go above and beyond like that, I don't know," Yazoo County Sheriff Tommy Vaughan told the Clarion-Ledger of the football player's actions.