Wayne County Judge Brian Sullivan noted in his ruling that a gun directly linked to the killings was found at a home used by a Smothers ally and said that some portions of Smothers' statement "do reflect a detailed depiction of the scene of the crime and a plausible version of what happened."
Nonetheless, the judge said, "Smothers' statement does not automatically exonerate" Sanford, now 19.
Smothers, who is serving a 52-year prison sentence for eight other murders, recently told the Associated Press that he's willing to go to court to explain that Sanford had no role. But the judge ruled that Smothers had earlier opportunities to speak.
Sanford's appellate lawyer, Kim McGinnis, has said that Sanford has a low IQ and was trying to please police when he walked up to investigators immediately after the killings. The teen's confession never was recorded, and McGinnis claims that police fed Sanford details about the crime scene.
The prosecutor's office has consistently fought to uphold the conviction, although it concedes that Smothers probably had a role. He never has been charged.
"There was insufficient evidence to support the withdrawal of Sanford's guilty plea that took place while the trial was in progress. We are very pleased with Judge Sullivan's decision denying his motion," spokeswoman Maria Miller said yesterday.
McGinnis said that an appeal was planned.
"It's a shame that an innocent kid has to stay in prison longer," she said. "It's a shame that Judge Sullivan would not permit testimony from the true perpetrator who wants to exonerate an innocent person."
The judge cited other issues in his 30-page decision. He said that a retired Detroit homicide investigator's insistence that he was with Sanford at the time of the killings was false, based on cellphone records. William Rice knew the boy because he was in a relationship with Sanford's aunt.
"Taken as a whole, such discrepancies do not lead to a conclusion that the defendant is innocent, under the clear and convincing evidence standard," Sullivan said.
Sanford is not eligible for parole until 2046. He's housed in a maximum-security prison in Ionia County after logging more than 100 misconducts since 2008, according to the Michigan Department of Corrections.