Cook County sheriff's detectives have exhumed the remains of eight young men killed by John Wayne Gacy, extracting DNA in hopes they can finally identify the bodies and "close the book, once and for all" on the notorious serial killer.



"For 25 of these families, there was some degree of justice, some degree of closure," Sheriff Tom Dart said, referring to Gacy's victims that have been identified. "For eight of the families there was not closure. . .Today, we are beginning the process to close the book, once and for all, on John Wayne Gacy."



Seven of the unidentified victims were found in Gacy's crawlspace in his home near Norwood Park, officials said. The eighth was found buried under concrete beneath Gacy's barbecue pit, they said.



The jawbones of the eight unidentified victims were exhumed from Homewood Memorial Gardens on June 1, and a lab at the University of North Texas developed full DNA profiles for four of them.



The bodies of the four other victims were exhumed from Chicago cemeteries for testing in September in hopes of getting better DNA profiles.



Dart encouraged anyone to come forward if they know of a young boy or man who disappeared between 1970 and Dec. 22, 1978 and suspects he may have been killed by Gacy.



"We really want to make sure that this is somewhat of a broad net we throw out here," Dart said. "These victims came primarily from the Chicago area, but they came (from) throughout the Midwest as well."



All of identified victims were white males between the ages of 14 and 21, Dart said. All of the unidentified victims are also white males, but their ages are unknown, he said.



Detectives believe the passage of time might actually work in their favor. Some families who never reported the victims missing and never searched for them could be willing to do so now, a generation after Gacy's homosexuality and pattern of preying on vulnerable teens were splashed across newspapers all over the world.



"I'm hoping the stigma has lessened, that people can put family disagreements and biases against sexual orientation (and) drug use behind them to give these victims a name," Detective Jason Moran said in one of several interviews he and others in the sheriff's office gave to The Associated Press before the department disclosed the exhumations publicly.



Added Dart: "There are a million different reasons why someone hasn't come forward. Maybe they thought their son ran off to work in an oil field in Canada, who knows?"



After so many years, the relatives could be anywhere, so the sheriff's department is setting up a phone bank to field calls from across the country.



Gacy, who is remembered as one of history's most bizarre killers largely because of his work as an amateur clown, was convicted of murdering 33 young men, sometimes luring them to his Chicago-area home for sex by impersonating a police officer or promising them construction work. He stabbed one and strangled the others between 1972 and 1978. Most were buried in a crawl space under his home. Four others were dumped in a river.



He was executed in 1994, but the anguish caused by his crimes still resounds today.



Just days ago, a judge granted a request to exhume one victim whose mother doubted the medical examiner's conclusion that her son's remains were found under Gacy's house. Dart said other families have the same need for certainty.



"They were young men with futures, who at some point had families that cared about their kid," he said. Until the dead are identified, "it's like they didn't even exist."



The plan began unfolding earlier in the year, when detectives were trying to identify some human bones found scattered at a forest preserve. They started reviewing other cases of unidentified remains, which led them back to Gacy.



"I completely forgot or didn't know there were all these unidentifieds," Dart said.



It was not a cold case in the traditional sense. Gacy admitted to the slayings and was convicted by a jury. But Moran and others knew if they had the victims' bones, they could conduct genetic tests that would have seemed like science fiction in the 1970s, when forensic identification depended almost entirely on fingerprints and dental records.



After autopsies on the unidentified victims, pathologists in the 1970s removed their upper and lower jaws and their teeth to preserve as evidence in case science progressed to the point they could be useful or if dental records surfaced.



Detectives found out that those jaws had been stored for many years at the county's medical examiner's office. But when investigators arrived, they learned the remains had been buried in a paupers' grave in 2009.



"They kept them for 30 years, and then they got rid of them," Moran said.



After obtaining a court order, they dug up a wooden box containing eight smaller containers shaped like buckets, each holding a victim's jaw bones and teeth.



Back in June, Moran flew with them to a lab in Texas.



"They were my carry-on," he said, smiling.



Weeks later, the lab called. The good news was that there was enough material in four of the containers to provide what is called a nuclear DNA profile, meaning that if a parent or sibling or even cousins came forward, scientists could determine whether the DNA matched.



But with the other four containers, there was less usable material. That meant investigators had to dig up four of the victims. Detectives found them in four separate cemeteries and removed their femurs and vertebrae for analysis.



At a meeting last week, the men who investigated and prosecuted Gacy reminded the sheriff that many victims were already lost when Gacy found them. One had not even been reported missing when his body was found floating in the Des Plaines River.



"I can almost guarantee you that one or two of these kids were wards of the state," said retired Detective Phil Bettiker. "I don't think anybody cared about them." Most of them were 17 or 18 years old and had been "through God knows how many foster homes and were basically on their own."



At the same time, they recalled, other people repeatedly insisted their loved ones were among Gacy's victims, but no evidence ever came to light confirming it.



"It's very conceivable that a kid in his teens didn't have dental records," said Robert Egan, one of the prosecutors who helped convict Gacy. "There could have been parents who would have loved to have brought in dental records but they didn't have any."



Dart doubts that all eight victims will be identified. But he is confident that the office will finally be able to give some of them back their names.



"I'd be shocked if we don't get a handful," he said. "The technology is so precise."



Don Babwin is a reporter for the Associated Press, Ryan Haggerty a reporter for the Tribune