The body of 13-year-old Curtis Walker was found floating in a river in a quiet southeast Atlanta suburb this afternoon, another apparent victim of the elusive killer or killers stalking this city's black children.

"It looks like the same kind of case," said De Kalb County public safety director Dick Hand as dozens of firefighters and police searched the muddy banks of the South River for clues in the youth's death.

A preliminary autopsy tonight showed that Walker had been asphyxiated, Hand said. No further details were available, but police have said that about half of the 20 black children murdered here in the past 20 months appeared to have been strangled or asphyxiated. The cause of death in six of the slayings is unknown.

One youngster, 10-year-old Darron Glass, remains missing. He was last seen in September.

Investigators theorize that there is a primary killer and possibly a "copycat" spurred by the publicity.

Firemen returning from a routine call spotted the body, floating face down in the river, as they crossed a bridge. Walker was identified from medical and dental records provided by the special police task force probing the disappearances and slayings.

Reporters at the scene where Walker's body was found strained against a yellow ribbon blocking access to the river and watched police handcuff a young man wearing a baseball cap and jeans and whisk him away in a police car. But one officer said he doubted the man was connected to the case.

All of the missing and murdered children were black; they ranged in age from 7 to 16. All but two were boys, mostly street-wise youngsters who hustled for quarters by carrying grocery bags around shopping centers.

Walker, a slightly built youngster who stood 5 feet tall and weighed 75 pounds, was one. He lived with his mother and three brothers in a small, two-bedroom apartment in Bowen Homes, a housing project in northwest Atlanta.

Like the other children, he had a penchant for roaming his litter-strewn neighborhood, past the McDonald's and Byron's Gunshop, where he often inquired about odd jobs. He had stopped at the gun shop to ask for work Feb. 19, when he was last seen.

Don Laken, a burly dog handler from Philadelphia who has volunteered his services in looking for the missing children, said one of his German shepherds had picked up Walker's scent and followed it to the rear of a school down the road from the gun store. Laken suggested that the boy had climbed into a vehicle with a stranger.

Police are baffled at how the killer or killers are able to lure the children without anyone noticing. Detectives hungry for information that might lead to the killer or killers moved among strangers at the scene today, asking if they have seen anything suspicious.

Police were nervous, barking at reporters to stay back as they jotted down possible leads.

Bob Wood, 42, owner of Hojac and Mickey's Quick Shop, said that on Thursday he saw someone suspicious -- a white man who appeared to be about 45, stood about 5-foot-7 and weighed at least 200 pounds.

"He walked into the store and wanted to know where to find the nearest taxi, said he wanted to get to his car pretty quick, that he's been walking up and down the river," Wood said, adding that the man said he was walking to the river to bid for the sewage line the county plans to install along the banks. "People have been coming out here for three years to walk that river and I know them all, but I never seen him before," Wood said.

Meanwhile, a shooting occurred today during a high-speed chase provoked when two city residents saw three whites "beckon to a couple of black children to get in their car," said police spokesman Benjamin Sims. No one was injured.

Two women saw the occupants beckoning from their car and shouted to the children to keep away, Sims said. The children fled, and the car circled the neighborhood and returned. The women enlisted help of another citizen, who chased the car and fired a gun at it. Police joined the chase, which ended in a parking lot at Atlanta-Fulton County Stadium.

"There were no kids and no evidence of wrongoding in the car," Said Sims. The two men were taken into custody for questioning by the special task force."

The man who fired the shot was charged with aggravated assault and released on his own recognizance, Sims said.