The 14-year-old student who opened fire on classmates in a horror mass shooting at Apalachee High School was on the radar of the FBI a year before the tragedy, it has emerged. 

The federal agency said it interviewed accused gunman Colt Gray, 14, and his father last year following 'several anonymous tips about online threats to commit a school shooting at an unidentified location and time.' 

Officials said Gray 'denied making the threats online' at the time, and the only action taken was to warn local schools to 'continually monitor' the troubled teen.  

At a press conference Wednesday night, officials named the four victims of the shooting as teachers Christina Irimie and Richard Aspinwall, and students Mason Schermerhorn and Christian Angulo, both 14. 

In its statement on interviewing Gray last year, the FBI said the online threats included 'photographs of guns.' 

'Within 24 hours, the FBI determined the online post originated in Georgia' the statement continued, saying the ominous threats were referred to the Jackson County Sheriff's Office 'for action.' 

Under questioning, Gray's father, who has not been named, told officers he owned hunting guns in his home, but Gray 'did not have unsupervised access to them.' 

The agency said after Gray denied the threats, Jackson County 'alerted local schools for continued monitoring' of the disturbed teen. 

Following the tragic shooting, a junior at Apalachee High School who was sat next to Gray revealed the gunman's chilling behavior moments before he opened fire - and how she and her classmates narrowly avoided death.