(CBS/AP) CHICAGO - Attorneys for a woman who for years doubted her 14-year-old son was a victim of serial killer John Wayne Gacy said Thursday that at lab concluded that DNA tests on the exhumed remains were not those of her son.
"We don't know who it is, but this is not her son," said Steven Becker, who represents Sherry Marino. Her son, Michael, was last seen alive in 1976.
The Cook County Sheriff's Department, which last year launched its own investigation into several unidentified Gacy victims, said it has not seen the lab results or been briefed by the attorneys, who appeared on a local television station Thursday to announce the test results.
The orthodontist who initially examined Gacy's victims said he's convinced his findings are correct.
"The dental identification is just 100 percent solid, absolutely no question," said Dr. Edward Pavlik. "We compared 32 teeth, probably half a dozen of them had very distinct fillings and every tooth was consistent with the dental records of Michael Marino."
Gacy, a building contractor and amateur clown, was convicted of luring 33 young men and boys to Chicago-area home and strangling them between 1972 and 1978, sentenced to death and executed in 1994.
The announcement by Becker and fellow attorney Robert Stephenson comes one year after a judge approved the exhumation of the body - done in September - that authorities identified as Michael Marino.
According to the attorneys, a section of the jawbone and a femur were tested. Scientists at a North Carolina laboratory compared the bone DNA to that provided by Sherry Marino, the attorneys said, and determined she was not the biological mother.
Late last year, Sherry Marino requested that the body, one of more than two dozen found in the crawlspace of Gacy's home in late 1978, be exhumed to determine if the remains buried at the cemetery were her son's.
Days later, the sheriff's department said it had exhumed the remains of several young men believed to be, but never identified, as Gacy victims.
During last year's hearing, Sherry Marino's attorneys said she wondered why the clothes on the remains did not match the clothing she remembers seeing her son wear the day he disappeared. Further, they said she never understood why it took more than three years to identify her son, despite the fact that she provided dental records shortly after the bodies were discovered.
But even the attorneys acknowledged there was strong circumstantial evidence that the remains - identified as "body 14" - were those of Michael Marino, including that the remains were found in Gacy's crawl space next to those of Marino's friend who disappeared the same day.
The attorneys said Thursday the lab's findings do not necessarily mean that Marino was not a Gacy victim, but that it raises questions, such as whether other victims may have been misidentified.
"We don't know where Michael Marino is but what we do know is he's not buried in Queen of Heaven Cemetery under a tombstone that says `Michael Marino,' " Becker said.