WAYNE WILLIAMS was convicted Saturday night on two counts of homicide. According to the prosecution, he was linked with the murder of at least 20 more black children in Atlanta. The police in that city think the number is even higher, and that he was probably responsible for the deaths of all but three of the victims. City officials have announced that they are so sure Mr. Williams is the mass killer sought for so long that they will disband a special task force of investigators who have been working on the case since 1980. Still, there seems to be a strain of uncertainty in Atlanta, and the mother of one victim--who herself had worked as an assistant to the defense team--asserted after the verdict that "there is no justice in America."

Why are people still troubled, and is their fear justified? To begin with, it is understandable that the families of children who were killed, but for whose murders Wayne Williams was not tried, may never be satisfied that he is the killer, in spite of police evidence to the contrary. If the police are so certain-- they must think--why didn't they try him for my child's murder? Grieving parents may find it difficult to understand the prosecutor's quite reasonable decision to go with the two strongest cases to the exclusion of all the others. Their frustration can be abated if Atlanta officials take the time to go over with each family the evidence that links their child to Wayne Williams. With time, we expect, most of them will be assured that their child's killer has been brought to justice.

Some have questioned a conviction based entirely on circumstantial evidence--but what evidence! A team of 100 federal, state and city investigators, working with scientists and forensic experts, put together a case of unprecedented strength, which withstood the rigorous assaults of the defense team. The quality of the evidence is underscored by the fact that the jury reached its unanimous verdict in a relatively short time. It sat through nine weeks of testimony and listened to all the claims and counterclaims on every piece of rug fiber and every bloodstain. The jury is best able to evaluate the evidence it did.

Finally, some people seem reluctant, even in the face of this conviction, to give up the fear that a kind of racist conspiracy lay behind the murder of the children. These people are not reassured by the fact that Mr. Williams was apprehended by a team headed by Atlanta's black police chief and a black FBI agent. He was convicted by a majority black jury, before a black judge. Doubters find no solace in the assurance of Atlanta Mayor Andrew Young and former mayor Maynard Jackson that justice has been done.

It's difficult to know how to reach this group except by continuing reassurance that all Americans cared about these children. The outrage and the desire to help were neither racial nor regional but truly national in scope. So, too, should be the reassuring peace of mind that comes when justice has been done.