One person is in custody after multiple law enforcement agencies responded Wednesday to a shooting at Apalachee High School in Winder, Georgia , that killed four people and left nine others hospitalized.

Two of those killed in the shooting were students. The other two were teachers.

Georgia officials identified the student victims as Mason Schermerhorn and Christian Angulo, both of whom were 14. The two adults killed were Richard Aspinwall, 39, and Christina Irimie, 53.

The suspect, identified as Colt Gray, a 14-year-old student, has been arrested and charged with murder.

Chris Hosey, director of the Georgia Bureau of Investigations, told reporters the suspect surrendered to a school resource officer.

Sources told CNN earlier Wednesday that about 30 people were injured in the days violence, including those who have been transported to hospitals with gunshots.

Investigators said there was no apparent relationship between the shooter and the victims but that its still early in the case and further information may emerge. Its not yet clear how the gunman might have obtained the firearm or brought it onto school property.

The FBI s Atlanta office revealed later Wednesday that the Jackson County Sheriffs Office interviewed the suspect and his father last year after the FBI received several anonymous tips about online threats to commit a school shooting.

The father stated he had hunting guns in the house, but the subject did not have unsupervised access to them, the FBI said in a statement. The subject denied making the threats online. Jackson County alerted local schools for continued monitoring of the subject. At the time, there was no probable cause for arrest or to take any additional law enforcement on the local, state, or federal levels.

Out of the nine injured, eight are students and one is a teacher, authorities said .

Neither Hosey nor Barrow County Sheriff Jud Smith were prepared to discuss the extent of the injuries at a news conference Wednesday afternoon.

Video from a helicopter operated by Atlanta News First showed at least one person being airlifted from the scene at Apalachee High, with multiple ambulances in the vicinity. Officials told the news outlet that the person being airlifted had been taken to Grady Memorial Hospital, a Level 1 trauma center in Atlanta.