Two teenage step-brothers were stabbed outside Curtis High School, from a fight that started inside the school, according to the Staten Island Advance.

A third teen – 16-year-old Larry Adeyanju of Westervelt Avenue – has been charged with felony assault and criminal possession of a weapon. One victim, age 15, received stab wounds to his chest and abdomen. The other, age 18, was stabbed in his left arm.

The victims and the alleged assailant all live together in a community residence in New Brighton.

Authorities told the Advance the fight started in a stairwell at about 10:40 a.m., and continued outside the building.

Afterward, Adeyanju was held at the dean’s office, where he tried to hide the bloody knife, a law enforcement source told the paper.