AUGUSTA, Maine — A prosecutor from Aroostook County tried to convince members of the state’s highest court on Thursday that the state should be able to use evidence from a 27-year-old manslaughter case against a Mount Desert man recently charged with aggravated criminal operating under the influence of intoxicants.

However, the defense attorney for Troy Hastey, 45, argued that when his client pleaded guilty to manslaughter more than two decades ago, an accompanying OUI charge was dismissed, and thus any evidence that alcohol was involved in that accident cannot be used against him now.

An Aroostook County grand jury indicted Hastey in February 2016, stating that on Dec. 12, 2015, in Houlton, Hastey “did operate a motor vehicle while under the influence of intoxicants or while having [a blood] alcohol level of 0.08 or more.”

The charge was elevated to aggravated criminal OUI because of Hastey’s previous conviction for manslaughter involving a fatal accident in which alcohol allegedly was involved.

According to BDN archives, police said Hastey, then 18, was driving under the influence of liquor on Jan. 19, 1990, when his 1978 GMC pickup truck crossed the centerline as he was headed south on North Street in Houlton. The truck hit a 1986 Chevrolet driven by Ella Grant, 53, of Houlton, who was killed in the collision.

Hastey pleaded guilty to manslaughter and was convicted in May 1991. He was sentenced to seven years in prison with all but two years suspended and four years probation.

In the current case, the state had intended to introduce evidence from the 1990 accident showing that Hastey’s 1991 conviction was “involving or resulting from” operating under the influence of alcohol.

The difference in a potential penalty for Hastey is significant. A first OUI offense in Maine, as long as there are no aggravating factors, is a misdemeanor punishable by no more than 364 days in jail and a maximum fine of $2,000. A charge of aggravated criminal OUI is a class C felony, punishable by up to five years in prison and a $5,000 fine.

Following a motion filed last year by Hastey’s attorney, Kirk Bloomer, the trial judge ruled that the state could present as evidence only the indictment and judgment from the manslaughter conviction, which did not indicate that the alcohol was involved.

The state appealed that decision to the Maine Supreme Judicial Court.

On Thursday, Bloomer told the Law Court that the state’s appeal should be dismissed. He argued that when Hastey pleaded guilty to manslaughter back in 1991, the OUI charge was dismissed. Superior Court documents showed only that Hastey was convicted of reckless and criminally negligent operation of a motor vehicle causing the death of another person.

Aroostook County Assistant District Attorney Kurt Kafferlin argued Thursday that the trial court erred in determining that the state was not entitled to introduce evidence other than the indictment and judgment in order to prove that Hastey’s manslaughter conviction was related to driving under the influence.

“How do you expect to prove a case 25 years later?” Supreme Court Justice Ellen Gorman asked Kafferlin.

He told the justices that Hastey had waived his right to a jury trial in the current case, so the state would hold a bench trial and all evidence, including from 1991, would be presented to a judge. He also said that the majority of the witnesses who were involved in the 1991 case were still around and available to testify.

“The sergeant who did the intoxilyzer just retired last year,” the prosecutor said. “One of the individuals at the accident scene who smelled alcohol on Hastey’s breath is an attorney in the area.”

Other justices pointed out out to Kafferlin how daunting it would be to try a case this old with allegations this “stale.”

Bloomer agreed.

“I’ve never had the state come back and try to use a charge that was dismissed against someone in a subsequent prosecution,” he said.

The Law Court will take the matter under advisement and issue a decision at a later date.