Updated

Two St. Louis high school students were badly injured after a classmate threw an unknown chemical substance on them.

Police were called around 10 a.m. to Sumner High School. Authorities say a 16-year-old male student threw something on a 14-year-old boy and a 16-year-old girl in the library. The students are in serious but stable condition with chemical burns on their faces.

The alleged attacker is in custody and authorities are trying to determine the chemical used in the attack.