That confession has been shown to contain several factual inaccuracies, including the wrong time when the boys were killed and the wrong manner in which the boys were tied up. The confession was never admitted as evidence in Echols' trial, though his lawyers argue that jurors heard news reports describing the confession.
At trial, a prosecution occult expert testified that the murders appeared to be part of a satanic ritual. That witness had a degree from a now defunct correspondence school in California, Echols' court filings say.
According to court papers filed by Echols' attorneys, no DNA from the defendants was found at the crime scene.
But the lawyers say evidence does point to another possible suspect -- Terry Hobbs, the stepfather of Steve Branch. Hair containing DNA consistent with Hobbs' was found on one of the shoelaces used to tie up another of the boys. Another hair found nearby had DNA consistent with that of a friend of Hobbs', who was with Hobbs in the hours before the boys disappeared.
An attorney for Hobbs told WPTY in Memphis that Hobbs "absolutely has nothing to do with the murder of these lovely children."
Echols' court papers acknowledge that the hair does not establish Hobbs' guilt.
Several well-known forensic experts, hired by Echols' lawyers, also dispute that Christopher Byers was sexually mutilated with a knife, as prosecutors had claimed at Echols' trial. They say that animals ate parts of his body -- only after he was killed.
Dr. Werner Spitz, a forensic pathologist, said at a news conference Thursday that the animal claw marks on the bodies were "obvious" and said the injuries could not have been caused by a knife.
Byers told ABC News that he now wants "justice" for his son and the other boys.
"They let down not just me and two other family members," he said of the government officials who handled the case. "They let down every citizen who pays their salary."