In the first formal announcement of police progress in solving the cases of 22 missing and murdered children here, the FBI said yesterday that they had "three or four suspects" in Atlanta's child killings.

But an FBI spokesman cautioned against too much optimism over imminent arrests. "We do not have any evidence at this time to present to a federal grand jury" or to a state grand jury, he said.

Wiley Thompson, a special agent in the bureau's Washington office, said the FBI suspects are not connected with the "pattern killings" -- those police believe were committed by the same person or persons.

Police theorize that three sets of killers have had a hand in the 20 child murders that have torn at the soul of this city: a killer responsible for possibly as many as half the murders; a "copycat" or "copycats" inflamed by publicity, and a miscellaneous group perhaps involving family or friends of the victims.

Atlanta Police Commissioner Lee P. Brown declined to comment on the FBI's announcement, but high-ranking law-enforcement authorities here said that the FBI developments were "nothing new."

Three county police chiefs who count one or more child murders in their jurisdictions said the FBI had not informed them about its progress, and they had no idea who the FBI suspects were.

Today, the FBI also said that a New York City man, Frankie Edmonds, 32, arrested Sunday with a 9-year-old black youth in his truck, has been all but ruled out as a suspect in the Atlanta cases.

Law enforcement authorities here have been operating for some time under the belief that a number of slayings are not connected. Fulton County District Attorney Lewis Slaton theorizes that as many as nine or 10 killers may be involved.

All the victims have been black children: 18 boys and two girls, ranging in age between 7 and 16.

Some investigators believe seven of the last eight cases are connected, partly because the children, all boys, possessed similar life styles -- hustling for a buck outside grocery stores and on the sidewalks -- and because several were either strangled, asphyxiated or suffocated.

"I'd link together all those type killings," said one official.

Some authorities believe that there may be as many as six suspects in unrelated cases, some of them being relatives, friends or acquaintances of the children.

Authorities also count among the unrelated cases the killings of the two girls. Angel Lanier, 12, was found tied to a tree near her home in southwest Atlanta, fully clothed, a pair of panties stuffed in her mouth. Though she was strangled with an electrical cord, police believe her death may have been related to drugs.

In the case of Latonya Wilson, 7, police suspect someone close to the family. The child had been sleeping in the bedroom of her northwest Atlanta home when she was reportedly abducted without other children in the room being awakened. Her body was found in the woods nearby four months later.

Also included in the cluster of unrelated cases is Eric Middlebrooks, 14, who was bludgeoned to death and found behind a bar near his home 24 hours after he disappeared. Police say he was threatened by other youths about testifying at a juvenile proceeding; he testified anyway. Revenge may be the motive behind his murder.

Patrick Rogers, 16, bludgeoned to death and dumped in the Chatahoochee River, represents another possibly unrelated murder to some investigators because of the manner of his death, as does Anthony Carter, 9, who died from multiple stab wounds.

There is considerable interest here in the case of Yousef Bell, on whose strangled body a green fiber was found -- material similar to that found on several other bodies.

Still, some police officers continue to isolate Yousef from the "pattern killings," possibly because his body was dumped in an abandoned school near the housing project where he lived and because he appears to have remained alive for some time after he disappeared. His clothes were freshly washed.

Nor do police connect the first two killings with "pattern deaths." Edward Hope Smith, 14, was shot to death and Alfred J. Evans, 13, was probably strangled.

Even though the FBI may well be able to arrest one of its suspects eventually, some law enforcement authorities worry over how the community would respond to arresting someone close to a family while the primary killer remains at large.

"You're asking for trouble and the loss of credibility in the community," said one official. It's better to risk "waiting longer and avoid arresting one of the unconnected suspects until you clear up the major killings. Bringing a weak circumstantial case now would be the worst thing in the world. Even if you had one good case on circumstantial evidence, the kind of case you might move on at other times, I would hesitate to move on it now, even if it were airtight."

But Fulton County District Attorney Slaton said he would not "hold up" presenting any child's murder case to a grand jury. "If we've got evidence on one isolated case we don't think is connected with the others, we wouldn't hold up on it."