The 16-year-old boy accused of shooting a man on a Metro train Tuesday was charged Wednesday with armed robbery, not assault with intent to kill, as previously was expected.

Hassan Graves, who will be tried as an adult, was arraigned Wednesday morning along with Andre Broadie, 19, who also was charged with armed robbery.

Metro Transit Police had said Tuesday that Graves would be charged with assault with intent to kill.

"The investigation is very active and additional charges are possible," Metro spokesman Dan Stessel said in an update Wednesday evening.

Graves robbed a man and then shot him after he fought back, charging documents say.

The 24-year-old victim was on board a Green Line train approaching the Anacostia station Tuesday afternoon with his girlfriend when Graves robbed him, court documents say.

The victim tried to get his money back and punched Graves. That's when Graves shot the victim in the upper back, the documents say.

The victim was conscious and breathing when he was taken to a hospital, Metro said. He had been released by 9:30 p.m. Tuesday.

Police identified the suspects from surveillance video in the station, News4 reported. D.C. police later saw them walking on the South Capitol Street Bridge.

"If you commit a crime, we are going to get you," said Jack Evans, chairman of Metro's board of directors.

Graves has been arrested several times previously, including for participation in an armed robbery of a 7-Eleven, court documents say.

Broadie's lawyer said his client was at the scene of the alleged crime but didn't hurt the victim.

Metro officials said they don't remember a previous shooting on a train.

Broadie and Graves were ordered held without bond. They're due back in court March 10.