Long before Hannibal Lecter, John Wayne Gacy was the poster boy for the criminally insane. The Iowa native brutally sexually assaulted and murdered at least 33 victims in the 1970s. But now, two criminal defense attorneys in Chicago say that Gacy likely had help abducting and killing at least three of the victims, and that one or more accomplices may still be at large. Here, a guide to the new developments in this "sordid saga":

What exactly was Gacy convicted of?
Gacy was executed in 1994 for his role in the abduction, rape, and murder of 33 boys and young men in the 1970s. In 1978, police found the remains of 29 of his victims in a crawl space under his Chicago-area home. (The others had been dumped in a nearby river.) Gacy was dubbed the "Killer Clown" because of his penchant for dressing up as a clown at children's parties.

Why is the case being re-examined?
Acting on a request from the family of a victim, attorneys Robert Stephenson and Steven Becker began combing through the evidence, and found discrepancies in Gacy's travel and work records that cast doubt on his involvement in three of the murders. According to the lawyers, Gacy was away from Chicago when two of the victims, Russell Nelson and Robert Gilroy, disappeared from the city in 1977. The lawyers say Gacy also likely did not have enough time to kidnap and kill a third victim, John Mowery, because Mowery was abducted in Chicago the night before Gacy was due to be in Michigan early in the morning.

Are there any suspects?
Authorities appear to be concentrating on an unidentified friend who was with Nelson the night he was abducted. The friend later demanded money from Nelson's mother in exchange for his help in finding Nelson. The friend also offered Nelson's two brothers work with Gacy's construction company.

How strong is the lawyers' case?
In an interview with MSNBC.com, Cook County Sheriff Thomas Dart said, "I definitely would not dismiss what they have said. It's not out of left field." Terry Sullivan, who was on the team that originally prosecuted Gacy, told WGN-TV in Chicago, "I felt from the beginning that there may be loose ends."

What's the next step?
Dart says that the lawyers gave him the names of several potential accomplices, and that he has asked his investigators to look into the new evidence.

Sources: Chicago Sun-Times (2), MSNBC.com, New York Daily News, WGN-TV