Cops added they are still on the hunt for an additional suspect ... who they say was captured on surveillance video brandishing a gun at the scene of the crime.
As we reported, Robinson was shot two times -- once in the glute and once in the knee -- after cops say two males attempted to rob him outside of a row of businesses in D.C.
Cops say after the suspects fired on the NFL player ... they fled the scene in a vehicle.
Robinson required surgery to fix the damage caused by the bullets -- but ultimately made a full recovery.