THE PUBLIC FACE of the sniper investigation is Montgomery County Police Chief Charles A. Moose. Authority over the massive hunt for the assailant or assailants is not solely in his hands; a host of federal, state and local agencies have been deployed to help bring this mayhem to an end. By designation, however, Chief Moose has been the major source of information about the shootings. In that respect, the public has begun to grow restive with the paucity of his communications about efforts to get the perpetrator off the streets. Chief Moose, for his part, believes that withholding some information police have about the sniper is vital to the investigation. Both sides have some justification; but an understandably complicated situation for both the police and the public was made even more difficult by yesterday's handling of a piece of news with a direct bearing on every parent and family member in the region.

The confirmation of yesterday morning's shooting death of 35-year-old Montgomery County bus driver and Prince George's County resident Conrad E. Johnson was one new shock for the region; another came in news reports saying that a letter found near the Saturday shooting scene in Ashland, Va., contained a threat against children. The threat reportedly prompted the decision by authorities in the Richmond area to close public schools both Monday and yesterday. Obviously that is the kind of information that is of interest to not only the authorities but also to parents and Washington area residents. Of the confirmed sniper shootings, one involved a 13-year-old boy. If, after all this, children continue to be explicit targets of the shooter, parents, indeed, have a right to know.

But during yesterday's midday briefing, Chief Moose refused to comment on reports about a sniper letter or the existence of wording that suggested that children might become targets of future attacks. It was only after reporters, some of whom had confirmed reports about the letter and its ominous wording, aggressively questioned the chief that the authorities relented, coming clean later in the day.

What happened was not a model for future communication. The chief referred to "a great deal of speculation as to a reference, a threat in the message previously received." Because of press inquiries and what he described as the "reporting of incorrect versions," Chief Moose said the authorities determined that it was important to release the exact language he said came in the form of a postscript stating, "Your children are not safe anywhere at any time."

It should not have taken a spirited news briefing to bring this chilling information to light. True, the sniper has shown a willingness to shoot indiscriminately without regard to race, gender, profession, time of day or location. But singling out children, even after all the deaths and woundings, still represents a ratcheting up of a threat that the public certainly needs to know about. If nothing else, the letter and its fear-inspiring words confirm that the caution and vigilance of parents are well-placed.

None of this is to suggest that the authorities are not doing all they can to protect the public. But the chief himself said yesterday that authorities are not able to "ensure anyone their safety in regard to this situation." All the more reason, therefore, for authorities to be as forthcoming as possible with the public.