Howard County police Tuesday charged a 40-year-old west Baltimore man in a that was caught on video and went viral on the internet.
Donnell Maurice Vannison was charged with second-degree assault and disorderly conduct, according to a written statement from the Howard County Police Department (HCPD).
Vannison may also be charged with trespassing on school property, said police spokeswoman Sherry Llewellyn.
Police said that Vannison, wearing a ski mask, struck a 16-year-old male student outside the school at 2:20 p.m. on Wednesday, March 21.
The student, who was captured on video striking back, will not be charged, said police.
"Investigators believe he (the student) was acting in self-defense," said the statement.
HCPD responded to the scene for a person reported unconscious, said Llewellyn.
"As the officer approached Vannison, he was already walking away, off of school property. The officer talked with him briefly and offered medical attention, which he refused," said Llewellyn.
The officer found Vannison "stumbling down the sidewalk, almost falling over" with "blood on his face," according to charging documents, which referenced several times that Vannison "kept trying to leave" the scene.
Initially, Vannison gave the officer a false name, according to the report.
After discovering through a computer search that the name was an alias, the officer verified the subject's real identity and "Mr. Vannison was later sent on his way," according to charging documents.
The officer and Vannison had been across the street from the school during their interaction, according to charging documents, and it wasn't until the officer returned to campus that he learned of Vannison's involvement in the fight.
"A short time later, the officer received the report of the assault," said Llewellyn. "He began investigating the details, which resulted in charges against the 15-year-old girl and Vannison."
A 15-year-old female student hit the 16-year-old and as a juvenile last week, said police. Vannison was friends with her family, according to Llewellyn.
Police ramped up patrols at the school at the end of last week but have since returned to normal staffing levels, said Llewellyn.
Vannison has a trial date set for June 6, according to HCPD.
This article was updated with additional details at 3:15 p.m. and 4:30 p.m. on March 27.