There are exceptions such as 16-18 year olds committing traffic offenses. Further the U.S. Attorney for the District has authority to charge those committing serious crimes such as murder and armed robbery, and they can be charged as an adult. In that case, the Corporation Counsel would not prosecute the same offender. Bear in mind that a single juvenile case might involve kids with widely different ages, so particular situations can vary all over the map in terms of process and those involved.
Many agencies work together in handling juveniles.
Further, the DC Public Schools may be involved in truancy cases. The CAC facilities are physically scaled down for children and special expertise is available. DC requires a speedy trial. There is a formal terminology employed to remind all persons in the system that they are not dealing with adults and there is special interest in rehabilitation. DC requires a speedy trial.