THE D.C. POLICE affidavit said 52-year-old DeWitt Stith admitted assaulting and raping a 12-year-old boy last January. Charged with two counts of first-degree child sexual abuse, Mr. Stith was held without bond pending trial on grounds that he posed a threat to the community. A mental health panel decided, however, that Mr. Stith was incompetent to stand trial.

Two weeks ago, the prosecution announced in court that the charges would be dropped and the accused could go free, even bypassing confinement in a secure psychiatric institution. The 12-year-old's mother can't understand how that could happen. She need look no further than D.C. law and the council. Under District law, mentally ill residents considered a danger to themselves or others can be civilly committed. The law, however, does not apply to mentally retarded residents. That explains why in September 1995 prosecutors also had to release a mentally retarded man who police said admitted he had strangled his roommate in a group home because he snored too loudly. It is the reason at least two other rapes since 1995 have gone unpunished, prosecutors say.

DeWitt Stith, while not prosecuted or committed to secure confinement, is not exactly free either. He's been placed in a D.C. group home, where he is supposed to be supervised around the clock. His attorney says this indicates the city is equipped to handle troubled mentally retarded residents. But Jearline Williams, director of the D.C. Department of Human Services (responsible for group homes), doesn't see it that way. She told Mayor Anthony Williams in her June 17 weekly report: "DHS concern is that while the agency will do everything in its power to provide for Mr. Stith's care and the protection of other [clients] and the community, the agency and its staff are not jailers and does not have the capacity to fully guarantee that Mr. Stith will not be a future threat to his peers or the general public."

In February 1997, then-U.S. Attorney Eric Holder asked then-Council Judiciary Committee Chairman Jack Evans (D-Ward 2), personally and then in writing, to change the law. No action was taken. Mr. Evans says prosecutors didn't push hard enough. Fortunately, the new Judiciary Committee chairman, Harold Brazil (D-At Large), doesn't have to be begged. A committee spokesman said yesterday, "We will act as soon as possible, and if we have to do it as emergency legislation, we will."