PITTSBURGH — A judge erred when he re-sentenced a former-teen killer to no more than 26 years in prison for the death of his drug-dealing partner over a $100 debt in 1992, a Pennsylvania appeals court ruled Monday.

The Allegheny County judge last year re-sentenced Regis Seskey — now 42 years old — based on the 2012 U.S. Supreme Court decision, Miller v. Alabama. That opinion said mandatory life sentences without parole amount to cruel and unusual punishment for juvenile offenders. Seskey was only 17 when prosecutors contend Seskey killed Bova because he was upset that Bova used too much crack cocaine and owed him money.

Seskey lured Bova to a field with the promise of more drugs, then fired five shots from a sawed-off shotgun, killing Bova. Afterward, Seskey went to a restaurant and told someone killing Bova “was like killing a rabbit,” according to Monday’s 10-page Superior Court ruling.

County prosecutors appealed the new sentence, saying the judge violated state law by not leaving in place a maximum life prison sentence. The Superior Court agreed.

Seskey’s attorney, Abe Delnore, had argued earlier this year that the judge had the discretion to re-sentence Seskey to any amount of prison time because judges in six other counties across Pennsylvania had done that in the wake of the Miller decision.

But the court agreed with Assistant District Attorney Michael Streily, who argued Common Pleas Judge Joseph Williams III erred in re-sentencing Seskey to 13 to 26 years in prison. Because he got credit for good behavior and time he spent in jail since his arrest, Williams’ re-sentence made Seskey immediately eligible for parole. He has remained in prison because of the district attorney’s appeal, however.

Streily argued the re-sentence was illegal because state law still requires a maximum life sentence for first-degree murder, even when the offender is a juvenile. Streily argued that the judge’s only discretion was how low the minimum sentence could be.

State laws passed since Miller say first-degree murder offenders who are 15 to 17 years old must receive at least 35 years in prison, with a life term maximum; and first-degree murderers under 15 must still receive at least a 30-year minimum sentence. The minimum sentence for juvenile offenders convicted of second-degree murder — a killing that occurs during another felony — is now 20 years, with the maximum still being life.

The Pennsylvania Supreme Court has ruled those sentencing limits for juveniles don’t apply retroactively to cases like Seskey’s, however, leaving open the question of how low Pennsylvania judges can go in setting minimum sentences when re-sentencing juvenile murderers convicted before the Miller decision.

Seskey’s appellate attorney, Abe Delnore, said he’s still “analyzing” Monday’s decision and hasn’t decided whether to appeal it. “We’re considering options,” he said.

Mike Manko, the district attorney’s spokesman, said, “Our office has been consistent in our approach to these re-sentencings by informing the court that the maximum sentence must still be life in prison with the minimum sentence having been set by the legislature at anywhere from 20 to 35 years depending upon the age of the victim at the time of the offense.”

No date has been set for the re-sentencing ordered by the appeals court.