Chicago police apparently failed since 1971 to follow up several leads that could have linked accused mass slayer John Wayne Gacy to homosexual rapes and the mysterious disapperance of local teen-age boys.

"If the police had only paid attention to us, they might have saved many lives, " said Marco Butkovich, whose son, John, 17 is one of the presumed victims. "I'd like to know what good are all their damn computers if they can't put two and two together."

Before young Butkovich disappered on July 31, 1975, he had been employed for about six months by Gacy, a convicted sex offender who operated a suburban interior remodeling business. The night Butkovich was last seen, he had a violent argument with Gacy over money, according to two other youths who were present.

"We told the police to go there and investigate," Butkovich's father, a custodian, said yesterday. "But they didn't do it. I talked to Gacy on the phone after that and he said the police never talked to him."

Neither did police talk with Robert Otera and Joseph Meronicki, friends of John Butkovich, who had gone with him to Gacy's home and witnessed the argument. The next morning, Butkovich's father said, he found his son's car a half-block from their home on the north side of Chicago with the key in the ignition and his son's wallet, containing $40, on the seat.

Gacy was arrested Friday after investigators found what may be the remains of as many as eight bodies under his house. Investigators said that Gacy had told them where to look for about two dozen more bodies.

Investigators using sledge hammers, power saws and pick axes unearthed three bodies today as they demolishe the Gacy home.

Cook County Medical Examiner Robert J. Stein said two of the bodies removed today from "shallow graves" under the house - and the other body not yet excavated - brought to five the total number unearthed.

The arrest and intensified investigation came several years after Gacy's name involved in several incidents involving the disapperance of teen-age boys or alleged homosexual acts. In addition to the Butkovich incident, four other instances which the police apparently did not pursue or at least link together:

A complaint from an unidentified teen-age boy on Feb9 12, 1971, that gacy had picked him up at the Greyhound Bus Station in Chicago and tired to force him into a sex act.

The disapperance in December 1976 of Gregory Godzik, 17, another of Gracy's employes.

The disapperance in January 1977 of a third Gacy employe, John Szyc, 19.

A complaint by Jeffrey Rignall, 27, that Gacy enticed him into a car last March 21 with a marijuana cigarette, then subdued him with a chloroform-soaked rag and raped him. Rignall said police failed to pursue his criminal complaint.

"I don't see what was different about my boy's case and the Piest boy's disapperance," said Eunice Godzik, mother of the youth who disappeared in 1977.

She was referring to the disapperance two weeks ago of Robert Piest, 15, a clerk in a suburban pharmacy, where he met Gacy, who had a remodeling contract there.

After the Piest youth disappeared, Cook County sheriff's officers obtained warrants to search Gacy's bungalow in the unincorporated area known as Norwood Park, just north of Chicago.

The first search of the house on Dec. 13 netted physical evidence that Priest had been there before he disappeared. Then sheriff's officers returned with another warrant Thursday, and found the remains of what may be eight bodies buried in a crawl space under the house.

Police said today that they found rubber sexual devices, chains and mirrors in Gacy's garage. One investigator said the garage was built over a filled-in swimming pool, and police fear that more bodies may be buried there.

Sheriff's Police Chief Edmund Dobbs, who is directing the search of Gacy's property, said the entire house would be dismantled if necessary. He estimated that the search would take about a week.

Gacy, 36, who was a paroled in 1970 after serving two years in prison on a sodomy charge in Iowa, was charged with the Piest youth's murder.

He told investigators where to look for what may be as many as 32 bodies of teen-age boys he said he had sexually molested and strangled.

Gacy moved to the Chicago area immediately after his 1970 parole. Although neither Iowa nor Illinois parole records were available for checking over the Christmas weekend, John Bedell, a member of the Iowa parole board, said it would have been necessary for Gacy to have approval of Illinois authorities to establish residence here.

However, authorities apparently didn't check Gacy's criminal record until the Piest boy disappeared from the pharmacy where he worked. His mother, Eilizabeth, had gone to the pharmacy to take Robert home for her 46th birthday celebration the night he disappeared.

"Mom, wait a minute," Elizabeth Piest quoted her son as saying the last time she saw him. "I've got to talk to a contractor about a summer job that will pay me $5 an hour."

She said she waited inside the pharmacy while Robert went outside to talk about the job. "That's the last time anybody saw him," his mother said. "It was my birthday, and we were going home to have cake."