A spokesman for the Cook County state's attorney's office says 19-year-old Silvonus Shannon, 18-year-old Eugene Riley and 16-year-old Eric Carson have been charged as adults. They were ordered held without bail on Monday afternoon.
Cook County prosecutors contend the defendants beat 16-year-old Derrion Albert to death by striking him with long planks of wood and stomping him in the head. Prosecutors say Albert was "merely a bystander" as two groups of students from different neighborhoods fought.
Security was increased at Albert's school on Monday, and a vigil is planned outside Fenger High School.