The lawyer for a man convicted of killing a 12-year-old girl more than 20 years ago told the state supreme court Thursday that DNA evidence warrants a new trial, while the prosecutor said the evidence was inconclusive and doesn’t stack up against a “mountain” of other evidence, including the defendant’s alleged confessions.

Lawyers clashed over Dennis Dechaine’s latest bid for a new trial, with Assistant Attorney General Donald Macomber accusing Dechaine of “perpetuating a fraud on the courts and the people of Maine” by continuing to proclaim his innocence in the kidnapping and killing of Sarah Cherry in July 1988.

“The state introduced a mountain of evidence the jury concluded that the state had proved beyond a reasonable doubt that Dennis Dechaine had killed and tortured Sarah Cherry,” he said.

Dechaine’s lawyer, Steven Peterson, told the justices they should order a new trial because the DNA evidence from the victim’s fingernail pointed toward someone other than Dechaine.

“This case isn’t over and it won’t be over until justice is done. The just result here would be a new trial,” he told reporters afterward. He said he would likely take the proceedings to federal court if the Maine Supreme Judicial Court rejects Dechaine’s appeal.

Dechaine, a Bowdoinham farmer who was 30 at the time of the killing, has maintained his innocence since he was convicted of kidnapping and slaying the girl from Bowdoin. Her body was found two days after she disappeared while baby-sitting in July 1988.

Macomber said the DNA evidence was inconclusive and was likely contaminated. But he said there was other evidence and pointed out that Dechaine confessed three times and told his lawyer the victim’s location before the body was recovered.

At one point, Justice Andrew Mead asked Macomber what was the harm of having another trial.

“The harm is sitting right over there,” he said, pointing to Debra Crosman, the victim’s mother, Chris Crosman, her stepfather, and other family members who were in the courtroom.

After the hearing, the family said they have no doubt of Dechaine’s guilt. “I hope I die knowing he’s still in prison and will never get out,” Debra Crosman said.