Metro Transit Police on Tuesday charged a 17-year-old Southeast D.C. teen with aggravated assault in connection with a brutal attack that occurred on the Red Line last month.

The assault occurred on a train traveling between Union Station and NoMA-Galludet about 5 p.m. on Dec. 21, as the train approached the NoMA platform. Metro said the adult victim was struck in the face, knocked unconscious and suffered serious injuries that required hospitalization.

The man’s wife said the 41-year-old suffered a concussion and a broken jaw and collarbone in the attack.

Metro Transit Police stopped the suspect at Gallery Place Metro station on Jan. 9, when an officer noticed that he appeared to match the image in a “be on the lookout” memo. The youth, found in possession of a BB gun, was arrested for possession of a prohibited weapon, Metro said.

Metro said the suspect’s name would not be released due to his age. He was held in custody pending a juvenile custody order, which was served Tuesday, Metro said, and he was charged with the Red Line assault.

Metro spokesman Dan Stessel said it is likely additional charges will be filed later.

“We do expect that there will be additional charges, potentially against additional suspects, in this case,” he said.

Metro Transit Police looking for six individuals in connection with Red Line attack

A witness to the assault told the Post that a rowdy group of youths had just boarded the train at Union Station when one of them began harassing a man, who was sitting down. The attack stemmed from an apparent attempted robbery of the man’s bag, Metro said.

Man suffers concussion, broken jaw on Metro’s Red Line in rush hour attack

An attacker began punching the man repeatedly before walking away, the witness said. Then, a second attacker punched him in the jaw. The man met his wife on the NoMa-Gallaudet station platform, where he was treated by paramedics and taken to a local hospital.

The man’s wife said this month that he is healing daily but has not been able to return to work.

‘I’m risking my life’: Some Metro riders worry as serious crimes rise