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More than 20,000 drunken-driving convictions in New Jersey could be in jeopardy after the state’s highest court ruled on Tuesday that breathalyzer tests used to win those judgments were inadmissible.

The unanimous ruling by the Supreme Court stems from criminal charges brought more than two years ago against a State Police sergeant who was accused of falsifying calibration records on breath test devices that were used in five of New Jersey’s 21 counties.

It is unclear how state courts and law enforcement officials will now proceed. The Supreme Court ruling does not automatically expunge all the drunken-driving convictions, but the justices did note that defendants tested by the affected breath machines could now seek to challenge their convictions. The decision also raises questions about cases that are still moving through the judicial system.

“We’ll be issuing guidance shortly for our county prosecutors and municipal prosecutors over how to handle those cases,” Gurbir Grewal, the New Jersey attorney general, said at a news conference on Tuesday.