The attorney for a teen charged with fatally shooting a friend at a south Florida high school says he will seek an insanity defense.

Teah Wimberly, who has been charged with second-degree murder, has severe depression and has suicidal thoughts. Attorney Larry Davis filed a motion saying 15-year-old Wimberly had been sexually molested by a family member and that her parents regularly beat her with a belt.

Authorities say Wimberly and 15-year-old Amanda Collette were longtime friends who recently stopped speaking before Wimberly shot her in November. She ran to a restaurant, called police and confessed.

The day before the shooting, court documents show Wimberly sliced her arms with a razor blade and warned students she was going to shoot someone and kill herself.