CHICAGO (CBS) — Cook County Sheriff Tom Dart says dozens of families have come forward in an effort to identify the remaining victims of serial killer John Wayne Gacy.

Dart says about 70 families, whose loved ones disappeared in the 1970s, have contacted the department.

Gacy is known to have killed 33 people in the Chicago area between 1972 and 1978.

Two Chicago-area families already have provided DNA samples and another family is set to be tested. DNA kits also have been mailed to Minnesota and Iowa authorities.

Dart says it will be weeks before authorities get the DNA comparisons back.

Investigators have exhumed the bodies of eight of the unidentified remains, in hopes of identifying all of his victims.

Anyone looking for information also can visit the sheriff’s website by clicking here. The website has general descriptions of the eight unidentified victims and the approximate date those victims would have disappeared.

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