ROCKLAND — The Knox County District Attorney’s Office will review all current and closed cases in which former Rockland police Officer Jacob Shirey was involved.

The decision announced Wednesday by District Attorney Jonathan Liberman comes after a state judge concluded that Shirey was not a credible witness and urged the review.

Shirey resigned on Jan. 9, 2017, from the Rockland Police Department for what the city said were personal reasons. His resignation came as he was under investigation for allegedly lying to supervisors about his activities while on duty, according to court documents. The allegations included going home and sleeping while on duty and denying he had done so.

“The integrity of convictions obtained by our office is of the utmost importance,” Liberman said in a prepared statement. He said the office staff will review open cases to decide whether further prosecution is warranted.

“And we will review closed cases to decide whether they should be reopened,” Liberman said.

The District Attorney’s Office provided information to defendants and their attorneys last year when it was informed by Rockland police that it had concerns about Shirey’s professionalism and honesty.

Justice Daniel Billings issued a ruling June 22 in Knox County Superior Court allowing Earle J. Studley of Union to withdraw his guilty plea in a drunken driving case.

Studley had pleaded guilty to charges of criminal operating under the influence and unlawful possession of suboxone stemming from an Oct. 11, 2013, traffic stop by Shirey in Rockland. He pleaded guilty in March 2015 and was given a two-year deferred disposition.

Before his scheduled sentencing occurred in July 2017, however, allegations arose about Shirey.

“This is not a situation where an officer’s credibility is brought into question by a single incident or a one-time mistake,” Billings said. “The Giglio materials document that former Officer Shirey has exhibited an ongoing pattern of dishonesty that raises questions about the outcome of any matter where his credibility was material to the outcome.”

Studley’s attorney, Christopher MacLean, has filed a motion to challenge the stop by Shirey, saying he had no reasonable suspicion to pull over his client.

In May 2017, Justice Bruce Mallonee ruled that the state was required to provide information it had concerning Shirey to defendants or their attorneys in 20 criminal cases. That ruling came after the District Attorney’s Office informed the court about credibility concerns with Shirey.

The U.S. Supreme Court, in the 1972 case Giglio vs. the United States, ruled that the prosecution is obligated to turn over evidence that could raise questions about the credibility of any government witnesses.

Billings also pointed out in his June 2018 ruling that he had found Shirey not credible in a September 2014 case. In that case, the judge said he did not find Shirey’s testimony credible about a traffic stop that led to a drunken driving arrest. The judge suppressed statements made by that defendant.

Shirey did not file a written report on that case until two months after the arrest and when he testified at a court hearing, he said he had a vivid memory of the reasons for the stop.

Shirey graduated from the Maine Criminal Justice Academy in May 2013 after joining the Rockland department in October 2012.