More than 4,000 people who paid up to $500 for a ticket crowded into the Civic Center last night to hear Sammy Davis Jr. and Frank Sinatra in a concert to raise money for the investigation of Atlanta's child murders.

"These are not very happy days in Atlanta," Sinatra told the crowd, "and the whole world is saddened with the inhumanity that brings us together. I came here to express to the parents of the children brutally murdered my compassion and love. I weep with them and for them. I shed tears for the brothers and sisters and companions who find terror an everyday companion."

A spokesman for Mayor Maynard Jackson said ticket sales reached $140,000, with corporate contributions and donations from the city of Chicago and singer Kenny Rogers bringing the total to at least $210,000.

The money will be used to help pay the cost of the special police task force investigating the murders of 20 black Atlanta children.

Davis, introduced by Reynolds, told the crowd that entertainers can "use our talent as a weapon . . . to fight evil. That's why this kind of event can be put together. . . .

"I don't want anybody to get it into their heads, please, that this is party time . . .," said Davis. "It's one thing to be Sammy Davis Jr. and be up there with all the diamonds and rings and woo-woo-wah. But I ain't no better than the man walking the street looking for a job if I have no commitment to my fellow human beings."

Georgia Gov. and Mrs. George Busbee attended the show. Also noticed in the sellout audience were entertainers Burt Reynolds -- who is making a movie in Atlanta -- Roberta Flack and Dizzy Gillespie.

Earlier, police using dogs searched the Civic Center for bombs. An Atlanta police officer, who asked not to be identified, said security for the affair included Atlanta police, Georgia Bureau of Investigation agents, FBI agents, members of the special task force and helicopters circling above the auditorium.

A person claiming responsibility for the slayings wrote letters to the Atlanta Constitution and the Atlanta Journal scourning the concert and saying: "Consider . . . while everybody's watching Sammy and Frank, who'll be watching the children?"

A spokesman for Davis, publicist Billy Rowe, said the entertainer was troubled by the threat but decided not to "serve" the letter-writer by canceling the concert.

All of the victims' families were invited to the event, but officials said there was no way of telling whether they came.

The concert was followed by a champagne and caviar party at the Peachtree Plaa Hotel -- a reception open only to those who bought $100 tickets to the concert, believed to be the first fund-raiser ever held to finance a criminal investigation.

Those attending the concert offered differing reasons for their presence.

"I want to see 'Ol Blue Eyes,'" said Jean Scott of suburban Decatur. But her husband, Bill Scott, a teacher at Long Middle School, quickly added, "Also to help. I teach in the Atlanta school system and it's a way to help. This makes it easy."

James Martin of Atlanta said it didn't matter to him who was on stage. "I'm a new resident in Atlanta and I'm interested in this thing," he said. "I'm interested not only for my own family, but for everyone."

The bodies of 20 children have been discovered in the Atlanta area since July 1979. One child, Darron Glass, 10, who vanished last September, is still missing. Another, Joseph Bell, 15, has been missing for a week but police believe he is a runaway and have not added his name to their list.

Mayor Jackson said earlier this week that the investigation was costing the city about $7,700 per day.