Michael Hernandez, 18, was 14 years old when he allegedly slashed the throat of Jaime Gough, 14, and stabbed him several times before going to his first-period class as if nothing happened, The Miami Herald reported Monday.
Hernandez's attorney, Richard Rosenbaum, is planning to bring in three mental health experts who believe Hernandez met the legal definition of insanity when he killed Gough.
"A huge issue in this case will be to what extent is this young man mentally ill, and to what extent did his mental illness play a role in what he did, and how much he is responsible for his own actions," said Ewald Horwath, a psychiatrist at the University of Miami's Miller Medical School.
The state's experts say Hernandez has a personality disorder.
Rosie O'Donnell unveils nearly 50-pound weight loss
Putin thinks Obama would save him if he were drowning