The attorney for a white Chicago police officer who shot a black teenager 16 times said Friday his client didn’t tamper with his squad car’s dashcam after a Chicago news outlet reported this week the device was intentionally damaged.

The website DNAinfo Chicago obtained Chicago Police Department maintenance records through a public information request that show the dashboard video and audio recording device in officer James Van Dyke’s squad car was damaged and repaired at least twice in the months leading up to the October 2014 shooting death of 17-year-old Laquan McDonald. During the night of the shooting, the camera didn’t catch any audio.

The squad car video of the McDonald shooting contradicted accounts that McDonald lunged at officers, setting off weeks of protests, and accusations of a cover-up and demands for Chicago Mayor Rahm Emanuel’s resignation. The Justice Department also started a civil rights investigation into the shooting.

"Let me be very clear on this, my client had nothing to do with any tampering of an audio," Van Dyke attorney Dan Herbert told reporters after a preliminary hearing on Van Dyke's charges of first-degree murder. "If this audio was tampered with then it was tampered with by somebody other than Jason Van Dyke."

According to DNAinfo Chicago, maintenance records show that a day after technicians fixed the device’s wiring in June, it was intentionally damaged. The device was fixed a second time in October, but on the night of the shooting – just 12 days later – the system failed to record any audio. A review of videos downloaded from the system concluded that personnel failed to sync microphones, the report said.

Herbert said that officers do not have an assigned patrol car, suggesting that another officer could be to blame for the device not operating properly.

However, videos recordings from four other cars at the scene that night don’t have audio either. Several experts told the Associated Press in December that it’s plausible for a single squad car to have a glitch, but they couldn’t imagine how several vehicles would all lose audio.

Police spokesman Anthony Guglielmi said Friday that he said could not comment on whether Van Dyke tampered with the dashcam in his vehicle because the case is under investigation.

Chicago Police conducted an audit that determined that about 80 percent of the department's cameras did not have functioning audio systems and acknowledged some had been "maliciously" damaged by officers.

The department has taken a number of steps to try to regain the trust of the community. Interim Police Superintendent John Escalante warned officers that they would be disciplined if their dashboard cameras were not in working order or failed to turn on their dashcam microphones.

Guglielmi said Friday that the department now audits dashcams on a daily basis and that "officers and supervisors will be held accountable." Since the closer scrutiny began last month, 20 officers and supervisors have faced discipline ranging from reprimands to a few days' suspension, Guglielmi said, adding that "there is still work to do."

Van Dyke, who is charged with first-degree murder, has pleaded not guilty. His attorney told reporters Friday that the officer and his family have received death threats. He has no formal protection, but the police department is aware of the threats and "taking precautions," Herbert said.

He also said he's still considering making a request for a change of trial venue, because he says it will be "extremely difficult" to seat an impartial jury in Chicago. Other officers at the scene are also under investigation because of apparent discrepancies between what they said happened in their reports and what the video shows happened.

The Associated Press contributed to this report.