MEDFORD (CBS) — Twenty Medford police officers have been suspended for not following the department’s policy regarding details at a construction project in the city last year, according to the mayor and police chief.

Though the policy violations range, Medford Police Chief Jack Buckley confirmed that the officers had been paid money they were not entitled to and accepted the money. The violations occurred from Feburary to April 2018 during the Medford Square Bridge project.

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Buckley said the total amount paid was $17,000, and that some officers were paid more than others, with some getting as much as $2,000.

“As the new chief of this department, I’m concerned about how at the supervisory level this could happen, and we’re going to put safeguards in place,” Buckley said.

In a statement, officials said outside investigator Paul L’Italien, a retired Massachusetts State Police captain, reviewed all of the records during his months long investigation and presented his finding to the city.

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“As Mayor, I’m dismayed and disappointed with the actions of some members of the Medford Police Department,” Mayor Stephanie Burke said in the release. “However, I remain confident that in concert with the Chief of Police, we handled this matter swiftly, professionally and with veracity.”

According to a news release, 45 officers were investigated, resulting in 15 being fully exonerated, three found to have insufficient evidence against them, seven receiving written letter of reprimand and 20 suspended.

In addition to the suspensions, police said, the officers had to pay back any detail money they made as part of the violation.

“While I am disappointed in the findings of the investigation, I have faith in the women and men of the Medford Police Department and believe that the discipline imposed is appropriate to correct behavior,” Buckley said in the release. “There is no question in my mind that each and every officer involved has served this city well and will continue to do so.”

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Though some officers are still serving their suspensions, Buckley said some have completed theirs and are back on the job.