Two Chicago attorneys, Robert Stephenson and Steven Becker, have reexamined the case against John Wayne Gacy, one of history's most notorious serial killers. They concluded that it would have been unlikely that the contractor and amateur clown could have killed all 33 of his victims, 29 of which were found buried on his Chicago property back in the 1970s, the Chicago Sun-Times reports.

The findings were deemed "very fruitful" by Cook County Sheriff Thomas Dart, MSNBC reports:

“I definitely would not dismiss what they have said. It’s not out of left field. It’s well thought out."

There were three victims -- all of whom were discovered stuffed into a crawl space underneath Gacy's home -- whose disappearances and murders lend some credence to the theory. Robert Gilroy, 18, disappeared between 5 p.m. and 6 p.m. on Sept. 15, 1977; Gacy was proven to have been out of town in Pittsburgh from Sept. 12 to Sept. 16. Russell Nelson, an architecture student, disappeared outside a disco in October 1977, accompanied by a friend who had worked for Gacy. The friend, who is still alive, later "threatened" Nelson's mother and demanded money in exchange for his help in finding him. Finally, there was John Mowery, 18, who disappeared on the night of Sept. 25, 1977. Gacy was in Michigan the following morning at 6 a.m., however, making the timeframe unlikely. Another possible clue: Nelson and Gilroy were both suffocated with cloth in their mouths; Gacy had used rope and board to strangle the rest his victims, the New York Daily News notes.

Terry Sullivan, a member of Gacy's original prosecution team, supports the investigation, telling WGN-TV, "I felt from the beginning that there may be loose ends." A member of Gacy's defense team said his client had confessed to all 33 murders, and that he was standing by the single-killer theory. Gacy, who recently returned to headlines after Michelle Bachmann mistook him for American screen icon John Wayne on a campaign stop, was executed in 1993.