BOSTON — The highest court in Massachusetts overturned the murder conviction of a woman found guilty of killing her wife, saying a prosecution witness who testified about paint evidence at the scene “lacked the necessary expertise.”

After Monday’s Supreme Judicial Court decision was released, the northwestern district attorney’s office said it would try Cara Lee Rintala a fourth time.

Rintala’s wife, Annamarie Cochrane Rintala, was found strangled in the basement of the couple’s Granby home in 2010. Both women were paramedics.

Cara Lee Rintala’s first two trials ended with hung juries, but she was convicted of first-degree murder in 2016 and sentenced to life in prison without parole.

The prosecution’s case at the third trial relied heavily on the testimony of a paint quality engineer who said that paint found on and near the victim’s body was still fresh, even though medical experts testified that the body had been there for up to eight hours.

Prosecutors argued that Cara Lee Rintala used the paint to contaminate the crime scene.

The high court in its decision said the paint expert’s testimony “lacked the requisite reliability and therefore should not have been admitted” and because “it was significant and likely swayed the jury’s verdict, we conclude that the error was prejudicial, and we therefore vacate the judgment against the defendant.”

“We are overjoyed by the Supreme Judicial Court’s decision reversing Miss Rintala’s conviction,” said her appeals attorney, Chauncey Wood.

Cara Lee Rintala remains behind bars, but Wood said he would request a bail hearing.

First Assistant District Attorney Steven Gagne called the court’s decision “profoundly disappointing,” but added that in the interests of justice for the victim’s family, the case will be tried again.

“We ultimately think this case should be reached by a jury rather than an appellate court,” Gagne said in a statement.