Investigators did not find any evidence of concealed graves at a Chicago property infamous serial killer John Wayne Gacy once managed in the mid-1970s.
Using updated technology, Cook County Sheriff Tom Dart's office searched the property last month with infrared equipment, specially trained dogs and FBI specialists, Dart's office said in a release.
The search took place March 20 on the 6100 block of W. Miami Avenue in Chicago. Gacy not only used to manage the property, but his mother lived there for a time as well.
A St. Louis-based infrared imaging company recommended by the FBI did much of the work, according to a report the company produced. The work was done at night for about four and a half hours. Neither infrared imaging nor ground-penetrating radar located any "abnormalities" that were "indicative of clandestine grave sites," according to the report.
The sheriff's office spent $4,758 for the company to conduct the search. The company had been used by the sheriff's office in the past, spokesman Frank Bilecki said.
Agents from the FBI's field office also assisted, using specially trained dogs capable of detecting the scent of human remains that may have been buried as long as 150 years ago, sheriff's officials said. The dogs did not detect the presence of human remains.
Authorities searched inside and outside the property, according to the report.
Though Gacy was convicted and eventually executed for the deaths of 33 teenage boys and young men after his 1978 arrest, Dart partially reopened the case in 2011 to identify the unknown remains of eight of Gacy's victims. So far, one of the unknown bodies was identified. The renewed efforts have also led to families of missing people finding their family members alive, living elsewhere in the country.