Jared Cano was arrested on Aug. 16, 2011, when he was 16 and charged with threatening to discharge a destructive device and attempting to make, possess, throw, place, project or discharge a destructive device with intent to harm, as well as several drug charges related to marijuana, the Tampa Bay Times reported.
At the time of his arrest, police confiscated a journal, bomb making materials and cellphone videos in which he describes a plot to bomb Freedom High School in April 2012 and shoot "any survivors," including two assistant principals.
The state charged him as an adult, and in October of this year, Cano pleaded no contest to the charges against him.
Cano was sentenced Wednesday to 15 years in prison.
Cano's family members said they were disappointed with the sentencing.
"He's not going to be the same person in 15 years," Michael Butler, Cano's grandfather, said outside the courtroom. "You can kiss him off."