WHEN POLICE OFFICIALS are accused of wrongdoing, it is serious business. When the allegation is made to federal prosecutors--alleging that a D.C. deputy police chief improperly ordered the release of two robbery suspects, that should be a matter of high public concern. But when this results in a month-long federal investigation of the deputy and a finding of no evidence of any wrongdoing, the deputy in question has an equally serious and personally important concern: who made the allegations, why did the investigation take so long and what about any recourse against false accusations?

That is why the Washington Metropolitan Police Officials Association has asked U.S. Attorney General William French Smith to order federal prosecutors to provide more details of the allegations against Deputy Chief Alphonso D. Gibson. The complaint stemmed from an incident last December in which two men were charged with being accessories to a robbery. Robbery squad officials dismissed the charges, and Chief Gibson reviewed the case before releases were processed. Later, federal prosecutors received--Mr. Gibson suspects it was from another policeman--allegations that the two men released were related to Mr. Gibson and that he had improperly intervened on their behalf. On April 8, when the investigation was concluded, Stanley S. Harris, U.S. attorney for the District of Columbia, wrote Deputy Gibson that "there is no evidence whatsoever of any misconduct or wrongdoing on your part."

The result has been one understandably angry deputy chief, a concerned police organization and all sorts of unseemly gossip about relationships of police officers to each other and to the U.S. attorney's office. For the sake of Mr. Gibson, others in the department and the people who depend on their department for honest and effective law enforcement, Attorney General Smith should quickly clear the air.