Detectives have long wondered what secrets serial killer John Wayne Gacy and other condemned murderers took to the grave when they were executed — particularly whether they had other unknown victims. Now, the Cook County Sheriff’s Department is trying to find out by entering the killers’ DNA profiles into a national database shared with other law-enforcement agencies. Authorities hope to find DNA matches from blood, semen, hair, or skin under victims’ fingernails that link the killers to cold cases.
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