(CHICAGO) A student at Wendell Phillips Academy High School was beaten so badly by a school security guard in April he was taken to the hospital and received stitches, according to a federal lawsuit filed Wednesday.

Gregory Green, 18, who was a senior at the time of the April 22 beating, filed the lawsuit in U.S. District Court in Chicago against the security guard, Sunni Barnes, and the Chicago Board of Education.

The lawsuit alleges Green, who has since graduated from Phillips Academy and will attended Northern Illinois University in the fall of 2015, was in drama class when Barnes was called to the room because another student was being disruptive.

When the disruptive student was being escorted out, the drama teacher asked Green to watch the class and to report to her if anyone misbehaved, according to the suit.

After a few minutes, the suit claims some students “started to get rowdy,” prompting Green to tell the teacher. That’s when Barnes said, “Stop interrupting me.”

Green then returned to his seat, but Barnes followed him into the classroom and said, “I’ll slap the s— out of you,” the suit alleges. That’s when “Gregory took the bait and responded back” to Barnes’ threat.

The teacher then told Green to go to the dean’s office and he complied, the suit said.

The suit claims that, on the way to the dean’s office, Barnes “taunted” Green, calling him a “little b—-” and saying something to the effect of, “You’re lucky I can’t put my hands on you.”

Once in the office, Barnes “punched Green with such great force that Green immediately fell to the ground,” the suit said.

Despite another security guard’s attempts to intervene, Barnes then kicked Green while the 18-year-old was on the ground, the suit said.

The other security officer notified the authorities and an ambulance took Green to Mercy Hospital and Medical Center, where he received several stitches for his busted lip and medical treatment for a swollen eye and bruised ribs, the suit alleges.

Barnes, 45, of the 7300 block of South East End Avenue, was charged with battery causing bodily harm, a Class A misdemeanor, court records show. He is next scheduled to appear in court Aug. 4.

The seven-count lawsuit claims excessive force, assault and battery, negligence and, among other things, intentional infliction of emotional distress. It also seeks to hold the Chicago Board of Education responsible. Green is seeking an undisclosed amount in damages.

Chicago Public Schools’ spokesman Bill McCaffrey said he was unable to comment on the pending litigation.