HILLSBOROUGH - An Orange County grand jury Monday indicted the Hillsborough teenager who is accused of killing his father and then opening fire in the Orange High School parking lot.

About lunchtime Aug. 30, sheriff's investigators say Alvaro Castillo, 19, of 230 Lipps Lane drove a minivan stocked with pipe bombs, ammunition and other weapons to the parking lot of his old school.

Armed with a shotgun and rifle, Castillo got out of the van and set off some firecrackers or a smoke bomb, according to sheriff's deputies. They say he fired at least one of the guns several times before being subdued by a student resource officer and a a driver's education teacher who is also a reserve officer and retired state trooper.

Two students were injured, one from a bullet grazing her shoulder and one from broken glass resulting from a gunshot, according to sheriff's deputies.

After his arrest, deputies found Castillo's father shot to death in the family's home.

The teenager, who was admitted to a hospital last spring after expressing suicidal thoughts, is being held for safekeeping in Raleigh's Central Prison.

The grand jury indicted Castillo on charges of first-degree murder, three counts of possession of weapons of mass destruction, assault with a deadly weapon with intent to kill inflicting serious injury, assault with a deadly weapon with intent to kill, discharging a weapon on occupied property, two counts of possessing a gun on educational property, and discharging a firearm on educational property, according to Orange-Chatham District Attorney Jim Woodall.

Woodall said he decided not to pursue charges of injury to personal property, which were misdemeanors, but added the charge of discharging a firearm on educational property, a felony.

An indictment means a grand jury has found probable cause to support the charges, so the case proceeds to Superior Court, where felonies usually are tried.